Institute of Physics of Materials AS CR, v. v. i. > Groups > Multiscale Modelling and Measurements of Physical Properties

Multiscale Modelling and Measurements of Physical Properties

Headdoc. Ing. Roman Gröger, Ph.D.
E-mail [javascript protected email address]
Phone number+420 532 290 448
Room307



The main purpose of our research activities is to elucidate how functional properties of materials depend on their underlying atomic structure, types of crystal lattice defects and their spatial arrangement, dimensionality of nanostructures and surface properties. We currently focus on heteroepitaxial semiconductor films based on III-nitrides (2D structures, thickness 10-1000 nm), magnetic nanoparticles (Fe3O4, nanocubes 10-50 nm), aggregates of magnetic nanoparticles with low fractal dimensions (D <2) and macroscopic low-temperature behavior of transition metals. This research is carried out using a wide range of theoretical models (DFT, atomic models based on empirical and semi-empirical potentials, Monte Carlo, Landau-Ginzburg, cellular automata, Master equation), which are combined with experimental studies using electron microscopy (TEM, STEM, SEM, EBIC, EBSD), scanning probe microscopy (AFM, MFM, CPEM). We are developing several theoretical models for interpretations of the EBIC current, magnetic diffraction spectra, properties of magnetic nanoparticles and yield criteria for predictions of the onset of plastic deformation in bcc and hcp metals.



Research directions:



  • elucidation of the origin of threading dislocations in III-nitride semiconductor heterostructures

  • formulation of ionic-covalent semi-empirical potentials for studies of extended defects in III-nitrides

  • synthesis, characterization and functionalization of nanoparticles for biology

  • development of equipments for measurements of specific absorption rates of magnetic nanoparticles in alternating magnetic fields

  • characterization of functional properties of materials using TEM (STEM), SEM (EBSD, EBIC), SPM (AFM, MFM, nanoEBIC, CPEM)

  • theoretical models for interpretations of EBIC contrast and of magnetic neutron diffraction spectra

  • experimental and theoretical studies of plastic deformation of bcc metals (V, Nb, Ta, Mo, W) incl. the effects of magnetism (Cr, Fe), and of hcp metals (Mg)

  • elucidation of the mechanisms of plastic deformation in high entropy alloys CoCrFeMnNi and in precipitation-strengthened FeNiCr steels

  • formulation of mesoscopic models of self-organization and pattern formation in correlated microstructural domains


Collaborations



  • University of Cambridge (UK)

  • ON Semiconductor (Czechia, Belgium)

  • CzechNanoLab/CEITEC (Czechia)

  • Istituto Italiano di Tecnologia (Italy)

  • Paul Scherrer Institut (Switzerland)

  • University of Pennsylvania (USA)

  • ICAMS and Ruhr-Universität Bochum (Germany)

  • Materials Growth & Measurement Laboratory (Czechia)


Researchers


NamePhone numbersRoomsE-mail
Mgr. Jan Fikar, Ph.D. +420 532 290 429421 [javascript protected email address]
Mgr. Andrej Ostapovec, Ph.D. +420 532 290 429421 [javascript protected email address]

Phd students


NamePhone numbersRoomsE-mail
Ing. Zdeněk Antoš +420 532 290 451308 [javascript protected email address]
Ing. Jakub Holzer +420 532 290 451308 [javascript protected email address]
Ing. Jakub Pongrácz +420 532 290 451308 [javascript protected email address]
Mgr. Tereza Sojková +420 532 290 451308 [javascript protected email address]
Ing. Petr Vacek +420 532 290 451308 [javascript protected email address]
M.Tech. Ritu Verma +420 532 290 461427 [javascript protected email address]

Diploma students


NamePhone numbersRoomsE-mail
Bc. Miroslav Husťák +420 532 290 451308 [javascript protected email address]


Project numberNameInvestigator
CZ.01.1.02/0.0/0.0/20_358/0023778 Correlative measurements of the magnetic properties of surfacedoc. Ing. Roman Gröger, Ph.D.
FW01010183 Next Generation of Integrated Atomic Force and Scanning Electron Microscopy (GEFSEM)doc. Ing. Roman Gröger, Ph.D.
19-23411S Interplay of plasticity and magnetism in alpha-iron and chromiumdoc. Ing. Roman Gröger, Ph.D.

ALL PROJECTS


Project numberNameInvestigator
8J19UA037 Non-Schmid behavior of dislocations in magnesium and its alloysMgr. Andrej Ostapovec, Ph.D.
763685 BACK FOR THE FUTURE (CZ)doc. Ing. Roman Gröger, Ph.D.
LQ1601 CEITEC 2020doc. Ing. Luboš Náhlík, Ph.D.
CZ.1.05/1.1.00/02.0068 CEITEC – Central European Institute of Technologydoc. Ing. Luboš Náhlík, Ph.D.
P204/10/0255 Calculation of the Peierls barrier in bcc metals and its dependence on stressdoc. Ing. Roman Gröger, Ph.D.
Marie-Curie International Reintegration Grant (IRG), No. 247705 “MesoPhysDef” Mesoscopic framework for modeling physical processes in multiphase materials with defectsdoc. Ing. Roman Gröger, Ph.D.

ALL PROJECTS

MightyEBIC 2.0 (Ephemeron Labs)

Contact person: doc. Ing. Roman Gröger, Ph.D.
Scan controller and data acquisition interface for making quantitative Electron Beam Induced Current (EBIC) measurements.

SPM LiteScope (NenoVision)

Contact person: doc. Ing. Roman Gröger, Ph.D.
Scanning Probe Microscope (SPM) designed for easy integration into the Scanning Electron Microscopes. The combination of complementary AFM and SEM techniques enables to use the advantages of both commonly used microscopy techniques. LiteScope incorporates a unique imaging technique "Correlative Probe and Electron Microscopy (CPEM)" enabling simultaneous acquisition of AFM and SEM data. LiteScope and the CPEM technology allow sample analysis in a way that was previously difficult or impossible by the two imaging technologies simultaneously.

3D Printer Prusa i3 MKS3+ & MMU2S (Prusa Research)

Contact person: doc. Ing. Roman Gröger, Ph.D.
The Prusa i3 MK3S+ 3D printer is the successor to the successful MK2 model. The main advantages of the MK3S+ include a redesigned extruder, a range of sensors and smart features.


2021

Ostapovec A., Kushnir K., Máthis K., Šiška F.: Interaction of Migrating Twin Boundaries with Obstacles in Magnesium. Metals 11 (2021) 154

Gröger R., Šremr J., Vydrová J.: Uniqueness and stability of activated dislocation shapes in crystals. Model. Simul. Mater. Sci. Eng. 29 (2021) 025006

Holzer J., Chlup Z., Kruml T., Gröger R.: Plastic deformation of magnetically isotropic Cr single crystals compressed at 77 K. Int. J. Plast. 138 (2021) 102938

Tinoco Navarro H., Holzer J., Pikálek T., Sobota J., Fořt T., Matějka M., Kruml T., Hutař P.: Determination of the yield stress in Al thin film by applying bulge test. Journal of Physics: Conference Series 1777 (2021) 012030

Heczko M., Mazánová V., Gröger R., Záležák T., Hooshmand M., George E., Mills M., Dlouhý A.: Elemental segregation to lattice defects in the CrMnFeCoNi high-entropy alloy during high temperature exposures. Acta Mater. 208 (2021) 116719



2020

Fikar J., Schäublin R.: Stability of small vacancy clusters in tungsten by molecular dynamics. Nucl. Instr. Meth. Phys. Res. B 464 (2020) 56-59

Šťastný P., Vacek P., Trunec M.: Characterization of microstructure and phase distribution of sintered multiphasic calcium phosphate bioceramics. Ceram. Int. 46 (2020) 5500-5504

Antoš Z., Vacek P., Gröger R.: Intersections of two stacking faults in zincblende GaN. Comp. Mater. Sci. 180 (2020) 109620

Gröger R., Vítek V.: Single crystal yield criterion for chromium based on atomistic studies of isolated 1/2[111] screw dislocations. Int. J. Plast. 132 (2020) 102733

Gröger R., Vítek V., Dlouhý A.: Effective pair potential for random fcc CoCrFeMnNi alloys. Model. Simul. Mater. Sci. Eng. 28 (2020) 075006

Ostapovec A., Serra A.: Review of Non-Classical Features of Deformation Twinning in hcp Metals and Their Description by Disconnection Mechanisms . Metals 10 (2020) 1134-1154



2019

Vacek P., Kostelník P., Gröger R.: Correlation of Structure and EBIC Contrast from Threading Dislocations in AlN/Si Films. Phys. Stat. Sol. B 256 (2019) 1900279

Ostapovec A., Gornakova A.: On faceting of {10 -11} and {10-12} twin boundaries in hcp metals. Mater. Lett. 247 (2019) 99-101

Que Z., Seifert H., Spätig P., Zhang A., Holzer J., Rao G., Ritter S.: Effect of dynamic strain ageing on environmental degradation of fracture resistance of low-alloy RPV steels in high-temperature water environments. Corros. Sci. 152 (2019) 172-189

Brož P., Zelenka F., Sopoušek J., Hejduková M., Sojková T., Zobač O.: Thermal analysis and Knudsen effusion mass spectrometry combined in a specially-adapted commercial skimmer coupled instrument (Netzsch). CALPHAD 65 (2019) 86-92

Que Z., Seifert H., Spätig P., Holzer J., Zhang A., Rao G., Ritter S.: Environmental degradation of fracture resistance in high-temperature water environments of low-alloy reactor pressure vessel steels with high sulphur or phosphorus contents. Corros. Sci. 154 (2019) 191-207

Que Z., Seifert H., Spätig P., Zhang A., Holzer J., Rao G., Ritter S.: Degradation Effects of Hydrogen and High-Temperature Water Environment on the Fracture Resistance of Low-Alloy RPV Steels. The Minerals, Metals & Materials Series (2019) 934-948

Gröger R., Vítek V.: Impact of non-Schmid stress components present in the yield criterion for bcc metals on the activity of {110}<111> slip systems. Comp. Mater. Sci. 159 (2019) 297-305

Ostapovec A., Serra A., Pond R.: Non-diffusional growth mechanism of I1 basal stacking-faults inside twins in hcp metals. Scr. Mater. 172 (2019) 149-153

Gröger R., Chlup Z., Sojková T., Kuběna I.: Interplay of slip and twinning in niobium single crystals compressed at 77 K. J. Mater. Res. 34 (2019) 261-270

Lee L., Frentrup M., Vacek P., Massabuau F., Kappers M., Wallis D., Oliver R.: Investigation of MOVPE-grown zincblende GaN nucleation layers on 3CSiC/ Si substrates. J. Cryst. Growth 524 (2019) 125167

Heczko M., Esser B., Gröger R., Feng L., Mazánová V., Wang Y., Mills M.: Structure, Morphology and Coarsening Behavior of MX (NbC) Nanoprecipitates in Fe-Ni-Cr Based Alloys. Microscopy and Microanalysis 25 (2019) 2612-2613

Lee L., Frentrup M., Vacek P., Kappers M., Wallis D., Oliver R.: Investigation of stacking faults in MOVPE-grown zincblende GaN by XRD and TEM. J. Appl. Phys. 125 (2019) 105303

Friák M., Buršíková V., Pizúrová N., Pavlů J., Jirásková Y., Homola V., Miháliková I., Slávik A., Holec D., Všianská M., Koutná N., Fikar J., Janičkovič D., Šob M., Neugebauer J.: Elasticity of Phases in Fe-Al-Ti Superalloys: Impact of Atomic Order and Anti-Phase Boundaries. Crystals 9 (2019) 299

Tinoco Navarro H., Holzer J., Pikálek T., Buchta Z., Lazar J., Chlupová A., Kruml T., Hutař P.: Determination of elastic parameters of Si3N4 thin films by means of a numerical approach and bulge tests. Thin Solid Films 672 (2019) 66-74


all publications