Contact

Dr. Matthias Posselt
Ion Induced Nanostructures
m.posseltAthzdr.de
Phone: +49 351 260 3279, +49 351 260 2199
Fax: +49 351 260 13279, +49 351 260 3285

Grundlagen und Simulation

In der Projektgruppe Grundlagen und Simulation werden atomistische Simulationen zum Verständnis der atomaren Dynamik, Kinetik und Thermodynamik in Festkörpern während der Teilchenbestrahlung und/oder thermischen und mechanischen Belastung eingesetzt. Schwerpunkt der Arbeiten bilden Untersuchungen von Eisenlegierungen und Halbleitermaterialien.

Forschungsschwerpunkte:

  • Thermodynamik und Kinetik von Defekten; Bestrahlungsinduzierte Defektbildung
  • Bildung und Eigenschaften von im Material eingebetteten Nanoclustern
  • Ionenstrahlmischen von Si- und Ge-Multischichtsystemen
  • Epitaktische Rekristallisation amorpher Si und Ge-Schichten

Methoden:

  • First-Principle-Simulationen
  • Molekulardynamik
  • Monte-Carlo-Simulationen
  • Zweierstoß-Simulationen
Energy_barriers_XW_MP ©Copyright: Dr. Posselt, Matthias

Fig. 1: Energy barriers an oxygen atom has to overcome during the diffusion in pure iron (green dashed line), and in the environment of a foreign titanium atom (black solid line). The numbers denote the possible neighbour positions of oxygen (red) relative to titanium (green). Due to the strong binding at the first and second neighbour position the oxygen diffusion slows down remarkably. This was also verified by the calculation of the diffusion coefficient by Atomistic Kinetic Monte Carlo simulations [X. Wang, M. Posselt, J. Faßbender, Phys. Rev. B 98 (2018) 064103].

Free_energy_MP ©Copyright: Dr. Posselt, Matthias

Fig. 2: Contributions of phonon excitations or lattice vibrations (thick line) and of the sum of phonon and electron (thin line) excitations to the free binding energy of vacancy and copper clusters vs. temperature. Since positive/negative energy means repulsion/attraction the combined effect of phonon and electron excitations leads to a loss of stability of the clusters with increasing temperature. At 1000 K this loss (related to the ground state binding energy)  is about 14 and 18% for v3 and v4, respectively,  and for Cu3 and Cu4 it is 36 and 45%, respectively [M. Posselt, M.  Devaraj, M. Schiwarth, Comput. Mater. Sci. 127 (2017) 284].

 

In der Gruppe arbeiten gegenwärtig: Dr. Matthias Posselt, Xiaoshuang Wang, Muthu Vallinayagam

Publikationen seit 2011:

X. Wang, M. Posselt, J. Faßbender: Influence of substitutional atoms on the diffusion of oxygen in dilute iron alloys, Phys. Rev. B 98 (2018) 064103

A. T. Al Motasem, M. Posselt, J. Bergström:  Nanoindentation and nanoscratching of a ferrite/austenite iron bi-crystal: An atomistic study, Tribol. Int. 127 (2018) 231

J. Kirschbaum, T. Teuber, A. Donner, M. Radek, D. Bougeard, R. Böttger, J. Lundsgaard Hansen, A. Nylandsted Larsen, M. Posselt*, H. Bracht*: Self-diffusion in amorphous silicon by local bond rearrangements, Phys. Rev. Lett 120 (2018) 225902

G. Bonny, A. Bakaev, D. Terentyev, E. Zhurkin, M. Posselt: Atomistic study of the hardening of ferritic iron by Ni-Cr decorated dislocation loops, J. Nucl. Mater. 498 (2018) 430

A. Bakaev, D. Terentyev, Z. Chang, M. Posselt, P. Olsson, E. E. Zhurkin: Effect of isotropic stress on dislocation bias factor in bcc iron: an atomistic study, Phil. Mag. 98 (2018) 54

N. Raja, D. Murali, M. Posselt, M. S. V. M.  Satyanarayana: High temperature stability of BaZrO3: An ab initio thermodynamic study, Phys. Stat. Sol. B 2017, 254, 1700398

M. Radek, B. Liedke, B. Schmidt, M. Voelskow, L. Bischoff, J. L. Hansen, A. N. Larsen, D. Bougeard, R. Böttger, S. Prucnal, M. Posselt, H. Bracht: Ion-beam-induced atomic mixing in Ge, Si, and SiGe, studied by means of isotope multilayer structures, Materials 10 (2017) 813

M. Posselt, M.  Devaraj, M. Schiwarth: Influence of phonon and electron excitations on the free energy of defect clusters in solids: A first-principles study, Computational Materials Science 127 (2017) 284

G. Bonny, A.  Bakaev, P. Olsson, C. Domain, E.  E. Zhurkin, M. Posselt.: Interatomic potential to study the formation of NiCr clusters in high Cr ferritic steels, J. Nucl. Mater. 484 (2017) 42

A. Bakaev, D. Terentyev, P. Grigorev, M. Posselt, E. E. Zhurkin: Ab intitio study of interaction of helium with edge and screw dislocations in tungsten, Nucl. Instr. Meth. B 393 (2017) 150

M. Radek,  H. Bracht,  B. Liedke, R. Böttger, M. Posselt: Ion-beam induced atomic mixing in isotopically controlled silicon multilayers, J. Appl. Phys. 120 (2016) 185701

A. T. Al-Motasem, N. T.  Mai, S. T.  Choi, M. Posselt: Atomistic study on mixed-mode fracture mechanisms of ferrite iron interacting with coherent copper and nickel nanoclusters, J. Nucl. Mater. 472 (2016) 20

D. Murali, M. Posselt,  M. Schiwarth: First-principles calculation of defect free energies: General aspects illustrated in the case of bcc Fe, Phys. Rev. B 92 (2015) 064103

M. Radek, H. Bracht, B. C. Johnson, J. C. McCallum,  M. Posselt, B. Liedke: Atomic transport during solid-phase epitaxial recrystallization of amorphous germanium, Appl. Phys. Lett. 107 (2015) 082112

Roisin A. Kelly, Bartosz Liedke, Stefan Baldauf, Anushka Gangnaik, Subhajit Biswas,Yordan Georgiev, Justin D. Holmes, Matthias Posselt, Nikolay Petkov: Epitaxial Post-Implant Recrystallization in Germanium Nanowires, Cryst. Growth Des.15 ( 2015) 4581

Shengqiang Zhou, Fang Liu, S. Prucnal, Kun Gao, M. Khalid, C. Baehtz, M. Posselt, W. Skorupa, M. Helm: Hyperdoping silicon with selenium: solid vs. liquid phase epitaxy, Sci. Rep. 5 (2015) 8329

A. Götze, S. Makowski, T. Kunze, M. Hübner, H. Zellbeck, V. Weihnacht, A. Leson, E. Beyer, J.-O. Joswig, G. Seifert, G. Abrasonis, M. Posselt, J. Fassbender, S. Gemming, M. Krause: Tetrahedral amorphous carbon coatings for friction reduction of the valve train in internal combustion engines, Advanced Engineering Materials 16 (2014) 1226

M. Posselt, D. Murali, B. K. Panigrahi: Energetics, structure, and composition of nanoclusters in Oxide Dispersion Strengthened Fe-Cr alloys, Modelling Simul. Mater. Sci. Eng. 22 (2014) 085003

M. Radek, H. Bracht, M. Posselt, B. Liedke, B. Schmidt, D. Bougeard: Temperature dependence of ion-beam mixing in crystalline and amorphous germanium isotope multilayer structures, J. Appl. Phys. 115 (2014) 023506

T. Kunze, M. Posselt, S. Gemming, G. Seifert, A. R. Konicek,  R. W. Carpick, L. Pastewka, M. Moseler: Wear, plasticity, and rehybridization in tetrahedral amorphous carbon, Tribol. Lett. 53 (2014) 119

M.Posselt: Importance of configurational contributions to the free energy of nanoclusters, AIP Advances 3 (2013) 072137

M. Talati, M. Posselt, G. Bonny, A. Al-Motasem, F. Bergner: Vibrational contribution to the thermodynamics of nanosized precipitates: vacancy–copper clusters in bcc-Fe, J. Phys.: Condens. Matter 24 (2012) 225402

H. Bracht, M. Radek, R. Kube, S. Knebel, M. Posselt, B. Schmidt, E. Haller, D. Bougeard: Ion-beam mixing in crystalline and amorphous germanium isotope multilayer structures, J. Appl. Phys. 110 (2011) 093502

D. Terentyev, L. Malerba, G. Bonny, A. T. Al-Motasem, M. Posselt: Interaction of an edge dislocation with Cu–Ni-vacancy clusters in bcc iron, J. Nucl. Mater. 419 (2011) 134

A.T. Al-Motasem, M. Posselt, F. Bergner: Nanoclusters in bcc-Fe containing vacancies, copper and nickel: Structure and energetics, J. Nucl. Mater. 418 (2011) 215

A. T. Al-Motasem, M. Posselt, F. Bergner, U. Birkenheuer: Structure, energetics and thermodynamics of copper-vacancy clusters in bcc-Fe: An atomistic study, J. Nucl. Mater. 414 (2011) 161


Bei Interesse an Bachelor-, Master-, Diplom- bzw. Doktorarbeiten melden Sie sich bitte bei Dr. Matthias Posselt (m.posselt@hzdr.de).


Contact

Dr. Matthias Posselt
Ion Induced Nanostructures
m.posseltAthzdr.de
Phone: +49 351 260 3279, +49 351 260 2199
Fax: +49 351 260 13279, +49 351 260 3285