PhD disertation themes – how to start?

1. Filip, Peter: Quantum oscillations in external fields

   (Kvantové oscilácie v externých poliach)
   —

   Supervisor: Filip, Peter, Mgr., PhD.

   Contact: peter.filipsavbask

    
2. Gendiar, Andrej: Quantum mechanics in the language of tensor networks

   (Kvantová mechanika v jazyku tenzorových sietí)
   —

   Supervisor: Gendiar, Andrej, Mgr., PhD.

   Contact: andrej.gendiarsavbask

   Goals:
   

   Properties of tensor-network states are investigated by the entanglement entropy in quantum spin models.

   Annotation:
   

   The tensor-product states (TPS) are frequently used in modern physics in order to obtain energies and eigenstates of quantum models. The typical systems to be studied are spin models whose Hamiltonians describe magnetism at zero temperature. By means of the tensor-product states, a quantum wave function (eigenstate) is approximated. The wave function contains both the physical degrees of the freedom, describing the Hilbert space, and the auxiliary (non-physical) degrees of the freedom, whose size controls range of the correlations, i.e., the accuracy. Many-body interacting spin systems are to be characterized by the TPS at the phase transition be means of the quantum entanglement. Since it is a non-trivial task, being non-analytically solvable, numerical approaches can be used, in particular, an arbitrary programming language can be freely applied, e.g., Python, MatLab, C++, etc. Novel alternative methods based on the tensor networks are to be proposed, which will originate in the renormalization techniques.

    
3. Kalinay, Pavol: Dimensional reduction of evolution equations in space constrained systems

   (Dimenzionálna redukcia evolučných rovníc v priestorovo obmedzených systémoch)
   —

   Supervisor: Kalinay, Pavol, RNDr., CSc.

   Contact: pavol.kalinaysavbask

    
4. Nagaj, Daniel: Quantum Hamiltonian complexity

   (Kvantová hamiltonovská zložitosť)
   —

   Supervisor: Nagaj, Daniel, Mgr., PhD.

   Contact: daniel.nagajsavbask

   Goals:
   

   Our aim at progress in Quantum Hamiltonian Complexity will come from probing multiple frontiers.

   Annotation:
   

   This project will focus on finding and investigating problems in (quantum) physics that translate to computationally hard problems, or systems with an interesting structure of the ground space. While foundational in nature, it could possibly find applications in cryptography or error correction. A complementary goal is to develop methods for classical simulation of quantum many-body systems, as well as testing toy-models using existing quantum software and hardware, with the aim of verifying larger scale quantum computations.

    
5. Nagaj, Daniel: Quantum optimization

   (Kvantová optimalizácia)
   —

   Supervisor: Nagaj, Daniel, Mgr., PhD.

   Contact: daniel.nagajsavbask

    
6. Plesch, Martin: Thermodynamics of quantum particles

   (Termodynamika kvantových častíc)
   —

   Supervisor: Plesch, Martin, RNDr., PhD.

   Contact: martin.pleschsavbask

   Goals:
   

   The aim to analyze thermodynamical properties of ansanbles of quantum particles

   Annotation:
   

   Quantum particles exhibit different collective properties in comparison to classical ones. Indiscriminability in connection with the existence of two fundamental species (fermions and bosons) lead to many peculiar and interesting results. The aim of the thesis is to investigate these affects and their influence on thermodynamical properties in mesoscopic systems, such as cells.

    
7. Plesch, Martin: Benchmarking of quantum computers

   (Benchmarking kvantových počítačov)
   —

   Supervisor: Plesch, Martin, RNDr., PhD.

   Contact: martin.pleschsavbask

   Goals:
   

   The aim ist o test and benchmark quantum computer accessible via cloud.

   Annotation:
   

   Small scale quantum computing has recently seen a large development, with IBM making their quantum processors accessible via cloud. With this step, quantum experiments on real quantum hardware became accessible to theorist all over the world. Additionally, other companies (e. g., Rigetti and Alibaba) are working on similar projects and their own quantum processors are becoming available to general public.

   Within th ework we will test quantum computers on protocols that have the potential to ba applicable also on small number of qubits, such as Variational Quantum Eigensolver.

    
8. Šamaj, Ladislav: Statistical mechanics of Coulomb systems

   (Štatistická mechanika coulombovských systémov)
   —

   Supervisor: Šamaj, Ladislav, RNDr., DrSc.

   Contact: ladislav.samajsavbask

    
9. Ziman, Mário: Quantum network communication and security

   (Kvantové komunikačné siete a bezpečnosť)
   —

   Supervisor: Ziman, Mário, doc. Mgr., PhD.

   Contact: mario.zimansavbask

   Annotation:
   

   Quantum network infrastructures represent a mid-term milestone in broad spread of quantum communication and computation technologies. Once available the question of its use arises. Quantum networks would be naturally of experimental interest aiming to characterize their features. Effcicient characterisation and optimal control and modeling of quantum information flows in the network are goals of this project. Apart of expected use for quantum key distribution, the network will provide an interesting testbed also for multi-partite communication protocols. Since this subject is relatively vivid and rapidly developing the particular research tasks will be specified during the PhD project. General objectives includes the development and design of multipartite communication protocols working under existing realistic conditions, thus, modifications of protocols to achieve noise resistance. Especially, we will focus on quantumenabled anonymity in such networks, proposals for distribution of quantum entanglement in large-scale networks and optimisation of routing protocols for quantum information transfer.

    
10. Ziman, Mário: Quantum verification methods

    (Kvantové verifikačné metódy)
    —

    Supervisor: Ziman, Mário, doc. Mgr., PhD.

    Contact: mario.zimansavbask

    Annotation:
    

    Certification of quantum state is an example of so-called inverse problem in quantum theory. The aim is to develop statistical verification methods to certify properties of quantum devices, specifically of quantum processes. This research is important for the experimental justification of the performance of quantum technologies.

     
11. Ziman, Mário: Quantum information structures in space-time

    (Kvantovo-informačné štruktúry v priestoročase)
    —

    Supervisor: Ziman, Mário, doc. Mgr., PhD.

    Contact: mario.zimansavbask

    Annotation:
    

    Recently the fields of quantum information and (loop) quantum gravity found common research interests. There is a believe the methods of quantum information theory are useful in quantum gravity. Indeed, some of the quantum gravity phenomena were already "simulated" on cloud quantum computers. The aim is to adapt the operational approach of quantum information theory for the analysis of physical principles of quantum gravity.

     
12. Ziman, Mário: Optimalisation of higher-order quantum structures

    (Optimalizácia kvantových štruktúr vyššieho rádu)
    —

    Supervisor: Ziman, Mário, doc. Mgr., PhD.

    Contact: mario.zimansavbask

    Annotation:
    

    Inevitable randomness of quantum theory manifests itself through quantum measurements. Their predicted outcome statistics is captured by Positive operator valued measures and if a description of post-measurement states is needed formalism of quantum instruments can be employed. More complex measurements can be built out of simpler ones by sequential use of the instruments or by interactions and measurements of ancillary quantum systems. The goal of this thesis is to understand potential of realizable measurements both in theoretical and in practical setting tailored for specific NISQ (noisy intermediate scale quantum) devices, such as IBM quantum experience, or other. We will therefore focus on simulability of instruments, efficient implementation of POVMs, and higher order measurements such as quantum testers.

     

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1. Boháč, Vlastimil:

   (Vývoj jednosondových senzorov a metód na vyšetrovanie tepelných vlastností materiálov)
   —

   Supervisor: Boháč, Vlastimil, Ing., CSc.

   Contact: vlastimil.bohacsavbask

    
2. Boháč, Vlastimil:

   (Vyšetrovanie termofyzikálnych vlastností poréznych materiálov pri simultánnom transporte tepla a vlhkosti)
   —

   Supervisor: Boháč, Vlastimil, Ing., CSc.

   Contact: vlastimil.bohacsavbask

    
3. Butvinová, Beata:

   (Vplyv špecifických vlastností povrchov kovových pások na ich magnetické vlastnosti)
   —

   Supervisor: Butvinová, Beata, RNDr., CSc.

   Contact: beata.butvinovasavbask

    
4. Gmucová, Katarína: Charge transport at the nanocomposite thin film / electrolyte interface

   (Transport náboja na rozhraní nanokompozitných vrstiev s elektrolytom)
   —

   Supervisor: Gmucová, Katarína, RNDr., CSc.

   Contact: katarina.gmucovasavbask

   Annotation:
   

   The thesis will be oriented toward the analysis of charge transfer phenomena at a nanocomposite thin film / electrolyte interface. Organic semiconductor based composites with embeded nanoparticles will be studied. A comprehensive understanding of the charge transfer kinetics at thin film / electrolyte interface is a key to developing both the prospective solar cells and electrochemical sensors based on electrochemical and combined electrochemical and optical signal transduction and readout. The complex analysis of charge transfer kinetics at nanocomposite thin films will contribute to the elucidation of anomalous charge transfer origin at nanostructured interfaces and to finding the chances of its applications in photovoltaics and sensorics.

    
5. Krajčí, Marián:

   (Počítačové modelovanie nanoštruktúr na povrchoch kovov)
   —

   Supervisor: Krajčí, Marián, RNDr., DrSc.

   Contact: marian.krajcisavbask

   Annotation:
   

    
6. Krajčí, Marián:

   (Katalýza chemických reakcií na povrchoch kovov)
   —

   Supervisor: Krajčí, Marián, RNDr., DrSc.

   Contact: marian.krajcisavbask

    
7. Mihalkovič, Marek: Search for and optimization of novel low-temperature structures

   (Vyhľadávanie a optimalizácia nových nízkoteplotných atómových štruktúr)
   —

   Supervisor: Mihalkovič, Marek, RNDr., CSc.

   Contact: marek.mihalkovicsavbask

   Annotation:
   

   Formulation of the problem is simple: given a set of chemical species, predict atomic structures they will form (at zero or finite temperature). Partial, yet critical steps in this process are search for energy-minimizing structures at given fixed chemical composition, or simpler, given the constraint of fixed numbers of atoms of each specie inside periodic cell. Even the latter, easiest problem is nowadays only solvable for up to several tens of atoms. This project will not focus on further development of the general methods, but rather adapt the current methods to selected challenging situations, when the expected optimal structrures have complex, hierarchical architecture.

   The succesful applicant will use a range of methods, starting from ab-initio quantum-mechanical calculations as implemented for example in widely used package VASP, through classical molecular dynamics and/or simulated annealing schemes using empirical interactions, to methods/algorithms for efficient searches through cohesive energy landscapes like genetic algorithm. The expected outcome of this postgraduate study will be prediction of novel complex atomic structures, and understanding of their formation mechanism.

    
8. Štich, Ivan: Study of nanostructures on strongly ionic surfaces and their charge manipulation

   (Štúdium nanoštruktúr na silne iónových povrchoch a ich nábojóvá manipulácia)
   —

   Supervisor: Štich, Ivan, prof. Ing., DrSc.

   Contact: ivan.stichsavbask

   Goals:
   

   Make use of computer modeling (primarily DFT) for understanding of formation and charge states of different nanostructures (oxygen atoms, pairs of oxygen atoms, oxygen molecules: peroxide and superoxide, gold clusters) on strongly ionic surfaces (TiO2, for instance) and tie them up with experimental AFM/KPFS results obtained by our partners at the Osaka University.

   Annotation:
   

   he project capitalizes on strong experiment-theory synergies, where the present project is in charge of the theory part and our partners at the Osaka University of the experimental part. Ionic surfaces, such as TiO2, form numerous atomic defects (oxygen and hydrogen defects, Ti interstitials) which form charged quasi-particles, polarons [1], which play a key role in formation of different nanoparticles (oxygen atoms, pairs of oxygen atoms, oxygen molecules: peroxide and superoxide, gold clusters) [1,2] on the surface. The nanoparticles are charged due to charge transfer to/from polarons as well as by KPFS nanomanipulation of charge by electron tunneling from/to the AFM tip. The project currently deals mainly with gold clusters on TiO2. These nanosytems and the associated charge-transfers will be studied by DFT methods and the results will be correlated with experimental AFM/KPFS results. The main project output will be publications in high-impact journals. The PhD. student will make a visit at our partner’s laboratories in Osaka and at the KCL, London.

   References:
   

   [1] Q. Zhang, Y.J. Li, H. F. Wen, Y. Adachi, M. Miyazaki, Y. Sugawara, R. Xu, Z. H. Cheng, J. Brndiar, L. Kantorovich, and I. Štich, Measurement and Manipulation of the Charge State of an Adsorbed Oxygen Adatom on the Rutile TiO2(110)-1×1 Surface by nc-AFM and KPFM,
   J. Am. Chem. Soc. 140, 15668 (2018).
   [2] Y. Adachi, H.F. Wen, Q.Z. Zhang, M. Miyazaki, Y. Sugawara, H. Sang, J. Brndiar, L. Kantorovich, I. Štich, and Y.J. Li, Tip-Induced Control of Charge and Molecular Bonding of Oxygen Atoms on the Rutile TiO2 (110) Surface with Atomic Force Microscopy, ACS Nano 13, 6917 (2019).

    
9. Štich, Ivan: Computational many-body study for electronic and photonic properties of 2D systems

   (Modelovanie elektrónových a fotonických vlastností 2D systémov počítačovými many-body technikami)
   —

   Supervisor: Štich, Ivan, prof. Ing., DrSc.

   Contact: ivan.stichsavbask

   Goals:
   

   Development and application of computational many-body techniques (primarily QMC- Quantum Monte Carlo) for ultra-accurate modeling of electronic and photonic properties of 2D systems (for instance optical and quasi-particle band gap, excitonic binding energies, etc.) Make use of this expertise for calculation of electronic-photonic properties of 2D systems under applied strain.

   Annotation:
   

   The project deals with development and application of computational many-body techniques (primarily QMC- quantum Monte Carlo) for ultra-accurate modeling of electronic and photonic properties of 2D systems. 2D systems have already revolutionized science, and have the potential to revolutionize also technology. In spite that, accurate determination of their electronic and photonic properties (for instance optical and quasi-particle band gaps, excitonic binding energies, etc.) is still a challenge. Customary techniques (DFT, GW, for instance) usually yield band gaps with errors of 1eV [1], rendering them of little use. Recently, we have shown, how these deficiencies can be eliminated using stochastic quantum Monte Carlo methods [1]. The PhD. student will engage in further development and application of QMC methods to 2D systems, primarily 2D systems under applied strain. It has been shown that strain is a very effective tool for tuning electronic properties of 2D materials [2]. The PhD. student will collaborate also with our partners at the North Carolina State University and at the University of Regensburg.

   References:
   

   [1] T. Frank, R. Derian, K. Tokár, L. Mitas, J. Fabian, and I. Štich, Many-Body Quantum Monte Carlo Study of 2D Materials: Cohesion and Band Gap in Single-Layer Phosphorene, Phys. Rev. X 9, 011018 (2019).
   [2] K. Tokár, J. Brndiar and I. Štich, Raman Activity of Multilayer Phosphorene under Strain, ACS Omega 4, 22418 (2019).

    
10. Švec, Peter: Multilayered and pseudobulk metallic glasses prepared by rapid quenching of the melt

    (Viacvrstvové a pseudoobjemové kovové sklá pripravené rýchlym ochladením taveniny)
    —

    Supervisor: Švec, Peter, Ing., DrSc.

    Contact: peter.svecsavbask

    Annotation:
    

    Analysis and selection of perspective chemical composition for systems of multilayered and pseudobulk metallic glasses derived from Fe and Co-based systems with enhanced glass forming ability.

    Development of methods of preparation of metallic glasses with increased thickness, preparation of metallic glasses with classical and enhanced thickness by planar flow casting. Development of alternative methods of preparation of pseudobulk metallic glasses.

    Analysis of structure and properties of as-quenched systems, analysis of the evolution of structure upon transition from as-quenched metastable state, comparison with classical metallic glasses. Assessment of glass-forming ability with respect to chemical composition and preparation technology.

     
11. Švec, Peter: Bulk metallic glasses prepared by rapid quenching of the melt

    (Objemové kovové sklá pripravené rýchlym ochladením taveniny)
    —

    Supervisor: Švec, Peter, Ing., DrSc.

    Contact: peter.svecsavbask

    Annotation:
    

    Analysis and selection of perspective chemical composition for systems of bulk metallic glasses derived from Fe-based systems with enhanced glass forming ability.

    Development of methods of preparation of metallic glasses with increased thickness, preparation of metallic glasses with classical and enhanced thickness by planar flow casting and by cold-mould casting. Development of alternative methods of preparation of bulk metallic glasses.

    Analysis of structure and properties of as-quenched systems, analysis of the evolution of structure upon transition from as-quenched metastable state, comparison with classical metallic glasses. Assessment of glass-forming ability with respect to chemical composition and preparation technology.

     
12. Švec, Peter: Formation of nanostructures and physical properties of metastable Fe and Co-rich systems

    (Vznik nanoštruktúr a fyzikálne vlastnosti metastabilných systémov bohatých na Fe a Co)
    —

    Supervisor: Švec, Peter, Ing., DrSc.

    Contact: peter.svecsavbask

    Annotation:
    

    Preparation, structure analysis and properties of Fe and Co-rich metallic systems containing suitable glass-forming and nanocrystal-forming elements (e. g. Nb, Cu, B, P, C, etc.) prepared by rapid quenching from the melt in metastable (amorphous) state.

    Analysis of thermodynamics and kinetics of structure evolution during transformation from metastable state; formation of nanocrystalline phases.

    Systematic optimization of composition and thermal treatment of selected systems with the aim of attaining appropriate combinations of magnetic and mechanical properties.

    Correlation of short-range ordering in as-prepared state with the local structure of phases formed during transformations and with the kinetics of their formation. Interpretation of the processes controlling phase transformations from disordered metastable state on atomic level.

     

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1. Jergel, Matej: Study of Few-Layer Thin Film Growth by In-Situ X-ray Scattering

   (Štúdium rastu atomárne tenkých vrstiev pomocou in-situ RTG rozptylu)
   —

   Supervisor: Jergel, Matej, Ing., DrSc.

   Contact: matej.jergelsavbask

   Goals:
   

   Research of few-layer thin-film growth in a CVD reactor utilizing X-ray scattering in real-time

   Annotation:
   

   The work will be focused on the kinetics of few-layer thin-film growth, including MoS2, PtSe2 and similar. To elucidate the kinetics of thin-film growth, in-situ grazing-incidence wide-angle X-ray scattering (GIWAXS) setup adapted to a CVD chamber will be used in a laboratory. Complementary GIWAXS experiments will be conducted at synchrotrons in Grenoble (ESRF) and Hamburg (DESY). The work will be realized at the Institute of Physics, SAS. For detailed information, please write an email to: peter.siffalovic@savba.sk or call +421949556037.

   References:
   

   1. M. Sojkova, et al., RSC Advances 9 (2019) 29645 - 29651

    
2. Jergel, Matej: In-operando diagnostics of Li batteries using optical methods

   (In-operando diagnostika Li batérií pomocou optických metód)
   —

   Supervisor: Jergel, Matej, Ing., DrSc.

   Contact: matej.jergelsavbask

   Goals:
   

   Study of charging/discharging cycles of Li-based batteries utilizing X-ray scattering and Raman spectroscopy

   Annotation:
   

   We will employ in-operando X-ray scattering and Raman spectroscopy studies to follow charging/discharging processes in Li-based batteries. We will focus on Li-S batteries due to their highest available capacity. We will track the phase and particle size changes during Li-ion intercalation utilizing wide- and small-angle X-ray scattering, respectively. Furthermore, we will use Raman spectroscopy in the range between 30 – 3600 cm-1 to follow the phase changes. Complementary to X-ray scattering, we will use cyclic voltammetry to track the charging/discharging processes. The work will be realized at the Institute of Physics, SAS. For detailed information, please write an email to: peter.siffalovic@savba.sk or call +421949556037.

   References:
   

   1. J. Nelson, et al., J. Am. Chem. Soc. 2012, 134, 14, 6337-6343

    
3. Majková, Eva: Advanced AFM and CLSM investigations for biomedical applications

   (Pokročilé AFM a CLSM metódy pre biomedické aplikácie)
   —

   Supervisor: Majková, Eva, RNDr., DrSc.

   Contact: eva.majkovasavbask

   Goals:
   

   Optimization and tracking of bioconjugated 2D materials utilizing advanced CLSM and AFM techniques

   Annotation:
   

   The topic will be focused on the applications of 2D materials for advanced biomedical systems. We have recently demonstrated that suitably bioconjugated 2D materials can have increased selectivity towards cancer cells, which is generally an important step to overcome the difficulties of currently in use cancer treatments. The research will be focused on the optimization of such high selectivity towards cancers cells. The experimental work will focus on the characterization of bioconjugation of 2D materials by confocal laser scanning microscopy (CLSM) combined with advanced atomic force microscopy (AFM) in a liquid environment. The work will encompass - detailed characterization of cells via AFM and CLSM, research and design of the functionalization of AFM tips for tethering different biomolecules, AFM single-molecule force spectroscopy characterization of biomolecules towards cell membranes. The work will be realized at the Institute of Physics and Virology Institute SAS. For detailed information, please write an email to: peter.siffalovic@savba.sk or call +421949556037.

   References:
   

   1. Lamprecht, C. et al., Biomedical Sensing with the Atomic Force Microscope, in Bhushan B. (eds) Nanotribology and Nanomechanics. 135–173 (Springer, 2017)
   2. Kálosi, A. et al., A bioconjugated MoS2 based nanoplatform with increased binding efficiency to cancer cells, in Biomater. Sci. 8, 1973–1980 (2020)

    
4. Šiffalovič, Peter: Bioconjugation study of emerging 2D photothermal nanomaterials

   (Biokonjugačné stratégie pre inovatívne 2D materiály vhodné pre fototermálnu terapiu)
   —

   Supervisor: Šiffalovič, Peter, Dr. Rer. Nat., PhD.

   Contact: peter.siffalovicsavbask

   Goals:
   

   Preparation, bioconjugation and optimization of 2D materials for targeted photothermal cancer therapy

   Annotation:
   

   The topic will be focused on the bioconjugation of 2D materials and their application in photothermal cancer treatment. We have recently demonstrated that suitably bioconjugated 2D materials can have increased selectivity towards cancer cells, which is generally an important step to overcome the difficulties of currently in use cancer treatments. Photothermal therapy triggered by irradiation of bioconjugated 2D materials can offer a breakthrough solution in the currently available therapies. The work will encompass – detailed characterization of cells and tissues via confocal Raman microspectroscopy, contribution to the preparation of nanostructures exhibiting photothermal properties, research and design of the bioconjugation of 2D photothermal nanomaterials (MoOx, MXene), in vitro and ex ovo studies with bioconjugated nanostructures, localization studies via confocal Raman microspectroscopy and complementary techniques (flow cytometry, confocal laser scanning microscopy) and optimization of the measurement conditions for different cell lines. The work will be realized at the Institute of Physics and Virology Institute SAS. For detailed information, please write an email to: peter.siffalovic@savba.sk or call +421949556037.

   References:
   

   1. Liu, S et al., Two‐Dimensional Nanomaterials for Photothermal Therapy, in Angewandte Chemie 132, 5943-5953 (2020)
   2. G. Song et al., Hydrophilic Molybdenum Oxide Nanomaterials with Controlled Morphology and Strong Plasmonic Absorption for Photothermal Ablation of Cancer Cells, in ACS Appl. Mater. Interfaces 6, 3915−3922 (2014)
   3. Kálosi, A. et al., A bioconjugated MoS2 based nanoplatform with increased binding efficiency to cancer cells, in Biomater. Sci. 8, 1973–1980 (2020)

    
5. Mrkývková, Naďa: Correlation between direct and reciprocal space mapping of thin films for optoelectronics

   (Korelácia priamych a reciprokých metód mapovania tenkých vrstiev vhodných pre optoelektroniku)
   —

   Supervisor: Mrkývková, Naďa, RNDr., PhD

   Contact: nada.mrkyvkovasavbask

   Goals:
   

   Study of thin films suitable for optoelectronics employing different direct and indirect optical techniques

   Annotation:
   

   The thin films possess quantum confinement due to the reduced dimensionality, which can significantly change the electronic and optical properties compared to their bulk counterparts. These materials offer great potential and opportunity for optoelectronic devices beyond traditional bulk materials.The aim of this thesis is to study thin films and other low-dimensional systems that are suitable for optoelectronic applications. For this purpose, direct optical methods such as near-field scanning optical microscopy (nanoFTIR) and indirect scattering methods (X-ray diffraction) will be used. The work will be realized at the Institute of Physics, SAS. For detailed information, please email to: nada.mrkyvkova@savba.sk or call +421 903 41 00 91.

   References:
   

   1. H. Lüth. Solid Surfaces, Interfaces and Thin Films, Springer, 2015, ISBN 978-3-319-10756-1.
   2. A. Zayats, D. Richards (ed.) Nano-Optics and Near-Field Optical Microscopy, Artech House, 2009, ISBN-13: 978-1-59693-283-8.

    
6. Mrkývková, Naďa: Novel flexible X-ray detector based on perovskite quantum dots

   (Nové ohybné RTG detektory na báze perovskitových kvantových bodov)
   —

   Supervisor: Mrkývková, Naďa, RNDr., PhD

   Contact: nada.mrkyvkovasavbask

   Goals:
   

   Study and characterization of thin films of perovskite quantum dots

   Annotation:
   

   The current X-rays detection technologies used in flat-panel detectors are mostly based on non-flexible and expensive silicon-based detectors. However, recent progress in low-dimensional perovskite materials (including perovskite quantum dots) enables the development of flexible, ultra-thin detectors with high absorption efficiency. This work will concentrate on the preparation and characterization of thin perovskite films (made of quantum dots) sandwiched between the electron and hole transporting layers. The perovskite layer effectively absorbs a photon, inducing a hole-electron pair, which will be in turn separated in the transporting layers. The work will be realized at the Institute of Physics, SAS, which poses all the necessary experimental equipment. For detailed information, please email to: nada.mrkyvkova@savba.sk or call +421 903 41 00 91.

   References:
   

   1. Y. Zhou, Y. Wang, Yan (eds.). Perovskite Quantum Dots. Springer, 2020. ISBN 978-981-15-6637-0.

    

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1. Bartoš, Erik: Behavior of fine-structure running constant in quantum electrodynamics in space-like and time-like region

   (Správanie bežiacej konštanty jemnej štruktúry v kvantovej elektrodynamike v priestorupodobnej a časupodobnej oblasti)
   —

   Supervisor: Bartoš, Erik, Mgr., PhD.

   Contact: erik.bartossavbask

   Goals:
   

   The reconstruction of the behavior of the lepton contribution to the running fine-structure constant in the time-like region and the finding its explicit shape in the space-like region.

   Annotation:
   

   The problem is related to the experimental measurement of the differential effective cross section of the elastic scattering of muons on atomic electrons Be or C, in the COMPASS experiment at CERN as a function of the square of the transferred momentum and the subsequent extraction of the behavior of the running coupling constant. It consists of contributions from leptons, five light quarks with a mass less than 5 GeV and a heavy "top" quark. In order to extract the hadron contribution from light quarks determining the LO of the hadron contribution to the anomalous magnetic moment of the muon, it is necessary to know the behavior of the lepton contributions in the space-like region. If in such a case it has the same logarithmic dependence as in the time-like region, since the square of the transferred momentum is negative, the complex value LO reaches the anomalous magnetic moment of the muon, which contradicts its classical evaluation using the dispersion relation over experimental values or ​R(s).

    
2. Běták, Emil:

   (Predrovnovážna emisia klastrov zo sférických a deformovaných jadier s uvážením spinových premenných)
   —

   Supervisor: Běták, Emil, doc. RNDr., DrSc.

   Contact: emil.betaksavbask

    
3. Filip, Peter:

   (Kvantové oscilácie častíc v hadrónovej hmote)
   —

   Supervisor: Filip, Peter, Mgr., PhD.

   Contact: peter.filipsavbask

    
4. Gmuca, Štefan:

   (Štruktúra kompaktných hviezd)
   —

   Supervisor: Gmuca, Štefan, Ing., CSc.

   Contact: stefan.gmucasavbask

    
5. Šauša, Ondrej: Positronium formation in cryoprotective mixtures suitable for deposition of living cells at low temperatures

   (Tvorba pozitrónia v kryoprotektívnych zmesiach vhodných pre depozit živých buniek pri nízkych teplotách)
   —

   Supervisor: Šauša, Ondrej, RNDr., CSc.

   Contact: ondrej.sausasavbask

   Goals:
   

   The melting and solidification of water in the presence of substances that suppress crystallization will be investigated using a positronium (Ps) probe.

   Annotation:
   

   Detailed investigation of the phase behavior of water in the presence of cryoprotectants such as DMSO, glycerol, ethylene glycol and selected carbohydrates, using changes in local free volume determined from the positronium lifetime during a wide temperature range. The combination of microscopic and macroscopic approach (positron annihilation time spectroscopy-PALS and differential scanning calorimetry, DSC) will contribute to a more comprehensive picture of the processes taking place in model mixtures at the microstructural level.

    
6. Šauša, Ondrej: Creation of positronium and study of crosslinking processes in new organic materials

   (Tvorba pozitrónia a štúdium procesov sieťovania v nových organických materiáloch)
   —

   Supervisor: Šauša, Ondrej, RNDr., CSc.

   Contact: ondrej.sausasavbask

   Goals:
   

   • Determination of temperature dependence of lifetime and intensity of Ps formation in bulk samples of dimethacrylate- and epoxide-based polymers after curing. Determination of local free volume changes over a wide temperature range of 20-300 K.
   • Comparison of microstructural parameters from annihilation measurements with the properties of studied substances by standard techniques such as DSC, DMTA, NIR.
   • Monitoring of changes in positronium formation over time during cross-linking processes, comparison with results of standard techniques (dielectric spectroscopy, NIR, DSC, EPR). Monitoring of various physicochemical effects on the evolution of crosslinking (composition, temperature, lighting).
   • Comparison of positronium formation in bulk and confined state in matrices with nanometer-size pores for selected matrix types and selected organic materials.

   Annotation:
   

   Study of microstructure changes in new organic materials based on dimethacrylates and epoxides in the processes of cross-linking by positron annihilation. The formation of positronium (bound state of e- and e+, Ps) as well as the lifetime of its triplet state (o-Ps) strongly depends on the structure of the material and allows (using appropriate models) to determine cavity sizes in the substance, such as intermolecular voids or pores in nanostructures in the range of 0.1-50 nm. Through changes in local free volume due to controlled changes in physical parameters (temperature, pressure, time), solidification, melting or aging evolutions in the investigated substances will be monitored. In this way, we can also observe the cross-linking processes (the evolution of the chemical reaction) in the formation of polymers and look for connections between the microstructure and the macroscopic properties of the studied substances. The effect of confinement selected organic materials in nanopores of suitable matrices on the physical properties of the confined substances by positron annihilation will be investigated.

    
7. Venhart, Martin: Studies of the nuclear structure using beam from the tandem accelerator

   (Štúdium jadrovej štruktúry pomocou zväzkov z tandemového urýchľovača)
   —

   Supervisor: Venhart, Martin, Mgr., PhD.

   Contact: martin.venhartsavbask

   Goals:
   

   • Performing of experimetns in Tandetron Laboratory in Piešťany
   • Studies of nuclear structure in the vicinity of Z = 28 closed shell
   • Identification of weak decay paths

   Annotation:
   

   Atomic nuclei exhibit shapes that may not be spherical. This has been known since ideas from the 1930’s. First hints of multiple shapes in a single nucleus were proposed in the mid 1950’s. Evidence for multiple shapes in nuclei has progressively built up but it is only recently that it has been realized multiple shapes may occur in a widespread manner. However, multiple shapes generally meant two shapes. There have been only a few examples where more than two shapes have been suggested. In a very recent study, based on detailed spectroscopic study and supporting state-of-the-art theory, multiple shapes are indicated in nuclei that were thought to be very well understood. This identification was based on the on the discovery of previously unknown, very-weak decay paths. Therefore, the ultra-high statistics studies are needed to identify such transitions. Such experiments are nowadays possible only in nuclei located at, or near the stability and long running times are required. Therefore, such a program is very well suited for the small-scale laboratories. Several months of the beam time can be used there. Such a long experiment would never be approved at large user facilities.

   
   Nuclei will be studied by means of coincident ɣ-ɣ spectroscopy, in combination with charged particles spectroscopy and conversion-electron spectroscopy. Excited states of interest will be studied with a combination of light-ion induced reactions, specifically (ɑ,ɑ’ɣ), (ɑ,ɣ), (ɑ,pɣ), (p,ɣ), (p,p’ɣ), and also radioactive decay. Experiments will be performed in the Tandetron laboratory of the Institute of Physics, Slovak Academy of Sciences. The tandem accelerator delivers beams of protons up to 4 MeV and ɑ particles up to 6 MeV. Various types of target systems are available, including the gas target. The array of scintillation and germanium detectors is operational, together with corresponding electronics.

   Note: Školiteľ špecialista: Mgr. Andrej Herzáň, PhD.

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1. Ivančo, Ján: Trioxide tungsten films aimed at chemiresistive sensors of gaseous biomarkers of diseases

   (Vrstvy trioxidu volfrámu pre chemoodporové senzory plynných biomarkerov chorôb)
   —

   Supervisor: Ivančo, Ján, Ing., PhD.

   Contact: jan.ivancosavbask

   Goals:
   

   Investigation on preparation and characterization of trioxide tungsten thin films and their sensing response towards trace concentration of acetone vapors.

   Annotation:
   

   The chemiresistive sensors of gases are based on resistance change of an active layer (usually metal oxides) upon the concentration change of gaseous ambient. For the particular probed gas, the sensor can be sensitive for its concentrations down to ppb level (parts per billion). The aplicant will investigate the preparation and physico-chemical properties of trioxide tungsten (WO3) and its sensing response to trace concentrations of acetone vapors in air. The research subject aims at noninvasive monitoring of elevated sugar level in blood of diabetics as the elevated sugar level is accompanied by increased acetone concentration in the exhaled breath.
   The work will be executed at Institute of Physics of Slovak Academy of Sciences. During the PhD study, the student is going to have an access to the autonomously equipped Laboratory of multilayers and nanostructures.

   References:
   

   • doi.org/10.2478/jee-2019-0053
   • doi.org/10.1039/c9cp02064k

    
2. Nádaždy, Vojtech: Electrical and structural properties of perovskite and organic semiconductors for photovoltaics

   (Elektrické a štruktúrne vlastnosti perovskitov a organických polovodičov pre fotovoltiku)
   —

   Supervisor: Nádaždy, Vojtech, Ing., CSc.

   Contact: vojtech.nadazdysavbask

   Goals:
   

   Efficiency and stability increase of perovskite and organic solar cells.

   Annotation:
   

   Perovskite solar cells (PSCs) are one of the hot topics in contemporary research in the 3rd generation photovoltaics. The PhD theme is focused on the preparation of perovskite and organic semiconductor layers utilized in PSCs and their systematic investigation in terms of electronic structure, crystallographic structure, morphology, interface properties and their impact on the photoconversion efficiency. Electronic structure of the layers will be investigated with a unique energy-resolved electrochemical impedance spectroscopy developed at the workplace of supervisor. Along with the analysis of other basic parameters of PSCSs such as the open-circuit voltage, short-circuit current, fill factor and power conversion efficiency, new basic knowledge on the correlation between electronic structure, electron transport properties and interface quality will be obtained.
   The work will be realized at the Institute of Physics, SAS.

    
3. Nádaždy, Vojtech: Preparation and electrochemical investigation of electrodes for secondary electrochemical cells

   (Príprava a elektrochemické vyšetrovanie elektród sekundárnych elektrochemických článkov)
   —

   Supervisor: Nádaždy, Vojtech, Ing., CSc.

   Contact: vojtech.nadazdysavbask

   Goals:
   

   Development of new generation of composite electrodes for rechargeable batteries.

   Annotation:
   

   Secondary electrochemical cells are rechargeable batteries that can be electrically recharged after use. This type of batteries plays an increasing role in dissemination of eco-friendly autonomous electrical facilities including vehicles. The PhD theme is focused on the development and preparation of new types of the composite cathodes and anodes for rechargeable lithium-ion and sodium-ion batteries. Using the methods of cyclic voltammetry, electrochemical impedance spectroscopy and cyclic charge-discharge, electrochemical properties of the electrodes will be studied aiming at increasing durability and improving efficiency of batteries. A unique method of the energy-resolved electrochemical impedance spectroscopy developed at the workplace of supervisor will be employed to characterize electronic structure of the electrodes. The work will be realized at the Institute of Physics, SAS.

    
4. Štich, Ivan: Modeling of structural and electronic properties of 2D van der Waals multilayers

   (Modelovanie štruktúrnych and elektrónových vlastností 2D van der Waalsových multivrstiev)
   —

   Supervisor: Štich, Ivan, prof. Ing., DrSc.

   Contact: ivan.stichsavbask

   Annotation:
   

   2D materials have already revolutionized science and have the potential to radically change also the technological applications. van der Waals (vdW) interaction is the most fundamental interaction of a 2D multilayer system, yet the most elusive one. vdW interaction crucially determines the electronic properties directly as well as indirectly via proximity effects, however, it cannot be directly addressed neither experimentally nor reliably theoretically via the customary density functional theory (DFT) approach. We will study vdW interactions by benchmark-quality fixed-node Monte Carlo methods [1], which trivially capture the vdW interaction and transfer the knowledge gained to the DFT domain [2] by DFT+vdW methods. The electronic properties will be correlated with the vdW-induced atomic structure and their description by standard DFT methods will be sought. We propose to study vdW interactions, energies, and the associated electronic properties for a series of carefully selected homo- and hetero-multilayers, bilayers of MoSe2 and graphene-MoSe2. The PhD. student will be supervised at IP SAS and work with IP SAS partners at Regensburg University and North Carolina State University, which the student will also visit, pandemic situation permitting.

   References:
   

   1. T. Frank, R. Derian, K. Tokár, L. Mitas, J. Fabian, and I. Štich, Many-Body Quantum Monte Carlo Study of 2D Materials: Cohesion and Band Gap in Single-Layer Phosphorene, Phys. Rev. X 9, 011018 (2019).
   2. K. Tokár, J. Brndiar and I. Štich, Raman Activity of Multilayer Phosphorene under Strain, ACS Omega 4, 22418 (2019).

    
5. Štich, Ivan: Study of nanostructures on strongly ionic surfaces and their charge manipulation

   (Štúdium nanoštruktúr na silne iónových povrchoch ich nábojová manipulácia)
   —

   Supervisor: Štich, Ivan, prof. Ing., DrSc.

   Contact: ivan.stichsavbask

   Annotation:
   

   The project capitalizes on strong experiment-theory synergies, where the present project is in charge of the theory part and our partners at the Osaka University of the experimental part. Ionic surfaces, such as TiO2, form numerous atomic defects (oxygen and hydrogen defects, Ti interstitials) which form charged quasi-particles, polarons [1], which play a key role in formation of different nanoparticles (oxygen atoms, pairs of oxygen atoms, oxygen molecules: peroxide and superoxide, gold clusters) [1,2] on the surface. The nanoparticles are charged due to charge transfer to/from polarons as well as by KPFS nanomanipulation of charge by electron tunneling from/to the AFM (Atomic Force Microscope) tip. The project currently deals mainly with gold clusters on TiO2. These nanosytems and the associated charge-transfers will be studied by density functional theory (DFT) methods and the results will be correlated with experimental AFM/KPFS results. The main project output will be publications in high-impact journals. The PhD. student will make a visit at our partner’s laboratories in Osaka and at the KCL, London.

   References:
   

   1. Q. Zhang, Y.J. Li, H. F. Wen, Y. Adachi, M. Miyazaki, Y. Sugawara, R. Xu, Z. H. Cheng, J. Brndiar, L. Kantorovich, and I. Štich, Measurement and Manipulation of the Charge State of an Adsorbed Oxygen Adatom on the Rutile TiO2(110)-1×1 Surface by nc-AFM and KPFM, J. Am. Chem. Soc. 140, 15668 (2018).
   2. Y. Adachi, H.F. Wen, Q.Z. Zhang, M. Miyazaki, Y. Sugawara, H. Sang, J. Brndiar, L. Kantorovich, I. Štich, and Y.J. Li, Tip-Induced Control of Charge and Molecular Bonding of Oxygen Atoms on the Rutile TiO2 (110) Surface with Atomic Force Microscopy, ACS Nano 13, 6917 (2019).

    

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1. Šauša, Ondrej: Photopolymerization in dimethacrylates investigated by positron annihilation

   (Fotopolymerizácia v dimetakrylátoch skúmaná pozitrónovou anihiláciou)
   —

   Supervisor: Šauša, Ondrej, RNDr., CSc.

   Contact: ondrej.sausasavbask

   Annotation:
   

   The goal of the project is to study the influence of physicochemical factors (temperature, light intensity, geometric factors, chemical composition and various chain transfer agents) on the course of photopolymerization and the resulting microstructural properties of new dimethacrylate-based polymers using positron annihilation spectroscopy (PALS). The course of polymerization in nanopores of translucent matrices will also be investigated. Positronium (Ps) will be a atomic probe for study the microstructure (local free volume) of the investigated materials. From the lifetime of Ps and the intensity of its formation, the sizes of free volumes, their distribution and the concentration of cavities in photopolymers will be calculated. The results obtained from the PALS technique will be compared with the results of other standard techniques such as differential scanning calorimetry, dielectric spectroscopy, infrared spectroscopy and electron microscopy. The source of positrons and subsequently also of the bound state Ps will be the radioisotope 22Na. The project presents an original application of nuclear methods in physico-chemical research of progressive polymeric materials.

    

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