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Dynamics, topological defects and phase transitions in ordered media

Grant number: 07/08492-9
Support type:Research Projects - Thematic Grants
Duration: June 01, 2008 - May 31, 2013
Field of knowledge:Physical Sciences and Mathematics - Physics - Condensed Matter Physics
Principal Investigator:Enzo Granato
Grantee:Enzo Granato
Home Institution: Instituto Nacional de Pesquisas Espaciais (INPE). Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brasil). São José dos Campos , SP, Brazil

Abstract

In many different physical systems, the symmetry breaking due the transition to an ordered phase allows for the existence of stable topological defects that have a dominant role in determining their physical properties. Such defects arise as a consequence of the periodicity and stiffness of the ordered media and are responsible for the mechanisms which lead to the phase transition. In atomic crystal lattices, for example, topological defects in the form of dislocations determine most of the plastic properties of the solids, both in the dynamics and statics. High temperature superconductors are another example of ordered media where the dynamics of topological defects in the form of vortices is predominant, being responsible for the resistivity of the superconducting material. Other important examples of ordered media where topological defects are dominant occur in crystal surfaces such as in strained epitaxial layers and boundary lubrication. In this case, the ordered media consists of one or several superposed atomic layers under the action of an external force induced by the substrate or by the other surface. Studies of the dynamics of defect nucleation, such as in the case of strained epitaxial layers in semiconductors, allows for a better understanding of the ordering mechanism and dislocation formation and may eventually help in the fabrication of structures and devices. In view of the possible applications of these structures in nanotechnology, it is of fundamental importance to advance the knowledge in this field. Likewise, studies of siding friction of lubricated surfaces are of great importance for nanotribology. The goal of the project is to develop theoretical research on the dynamics, topological defects and phase transitions in ordered media within a unified approach. The problems to be investigated and the analytical and numerical methods used are common to the different fields. Numerical methods based on Monte Carlo, molecular-dynamics and Langevin-dynamics simulations will be used in the studies of the relevant models. Important computational limitations like long execution times, due to the slow relaxation and of the systems, should be overcome by the use of parallel processing. Among the problems to be investigated are: vortex lattice and quantum fluctuations in superconductors, sliding friction on surfaces and dislocation nucleation in strained epitaxial layers. (AU)

Scientific publications (17)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
GRANATO, ENZO; YING, S. C.; ELDER, K. R.; ALA-NISSILA, T. Anomalous Fast Dynamics of Adsorbate Overlayers near an Incommensurate Structural Transition. Physical Review Letters, v. 111, n. 12 SEP 17 2013. Web of Science Citations: 5.
ELDER, K. R.; ROSSI, G.; KANERVA, P.; SANCHES, F.; YING, S-C.; GRANATO, E.; ACHIM, C. V.; ALA-NISSILA, T. Modeling self-organization of thin strained metallic overlayers from atomic to micron scales. Physical Review B, v. 88, n. 7 AUG 16 2013. Web of Science Citations: 10.
GRANATO, ENZO. Resistive transition in frustrated Josephson-junction arrays on a honeycomb lattice. Physical Review B, v. 87, n. 9 MAR 21 2013. Web of Science Citations: 10.
GRANATO, ENZO; YING, S. C. Evolution of Non-equilibrium Profile in Adsorbate Layer Under Compressive Strain. TRIBOLOGY LETTERS, v. 48, n. 1, SI, p. 83-88, OCT 2012. Web of Science Citations: 4.
ELDER, K. R.; ROSSI, G.; KANERVA, P.; SANCHES, F.; YING, S-C.; GRANATO, E.; ACHIM, C. V.; ALA-NISSILA, T. Patterning of Heteroepitaxial Overlayers from Nano to Micron Scales. Physical Review Letters, v. 108, n. 21 MAY 29 2012. Web of Science Citations: 43.
GRANATO, ENZO. Zero-temperature transition and correlation-length exponent of the frustrated XY model on a honeycomb lattice. Physical Review B, v. 85, n. 5, p. 054508, 2012. Web of Science Citations: 6.
GRANATO, E.; RAMOS, J. A. P.; ACHIM, C. V.; LEHIKOINEN, J.; YING, S. C.; ALA-NISSILA, T.; ELDER, K. R. Glassy phases and driven response of the phase-field-crystal model with random pinning. Physical Review E, v. 84, n. 3, 1 SEP 1 2011. Web of Science Citations: 10.
JALKANEN, J.; ROSSI, G.; TRUSHIN, O.; GRANATO, E.; ALA-NISSILA, T.; YING, S. -C. Stress release mechanisms for Cu on Pd(111) in the submonolayer and monolayer regimes. Physical Review B, v. 81, n. 4 JAN 2010. Web of Science Citations: 11.
RAMOS, J. A. P.; GRANATO, E.; YING, S. C.; ACHIM, C. V.; ELDER, K. R.; ALA-NISSILA, T. Dynamical transitions and sliding friction of the phase-field-crystal model with pinning. Physical Review E, v. 81, n. 1, 1 JAN 2010. Web of Science Citations: 32.
GRANATO‚ E.; YING‚ SC. Non-monotonic velocity dependence of atomic friction. TRIBOLOGY LETTERS, v. 39, n. 3, p. 229-233, 2010.
JALKANEN‚ J.; ROSSI‚ G.; TRUSHIN‚ O.; GRANATO‚ E.; ALA-NISSILA‚ T.; YING‚ S.C. Stress release mechanisms for Cu on Pd (111) in the submonolayer and monolayer regimes. Physical Review B, v. 81, n. 4, p. 041412, 2010.
GRANATO, ENZO; JUG, GIANCARLO. Spin-size disorder model for granular superconductors with charging effects. PHYSICA B-CONDENSED MATTER, v. 404, n. 19, p. 2916-2919, OCT 15 2009. Web of Science Citations: 1.
TRUSHIN, O.; JALKANEN, J.; GRANATO, E.; YING, S. C.; ALA-NISSILA, T. Atomistic studies of strain relaxation in heteroepitaxial systems. JOURNAL OF PHYSICS-CONDENSED MATTER, v. 21, n. 8 FEB 25 2009. Web of Science Citations: 5.
ACHIM, C. V.; RAMOS, J. A. P.; KARTTUNEN, M.; ELDER, K. R.; GRANATO, E.; ALA-NISSILA, T.; YING, S. C. Nonlinear driven response of a phase-field crystal in a periodic pinning potential. Physical Review E, v. 79, n. 1, 1 JAN 2009. Web of Science Citations: 22.
JALKANEN, J.; TRUSHIN, O.; GRANATO, E.; YING, S. C.; ALA-NISSILA, T. Equilibrium shape and size of supported heteroepitaxial nanoislands. European Physical Journal B, v. 66, n. 2, p. 175-183, NOV 2008. Web of Science Citations: 1.
RAMOS, J. A. P.; GRANATO, E.; ACHIM, C. V.; YING, S. C.; ELDER, K. R.; ALA-NISSILA, T. Thermal fluctuations and phase diagrams of the phase-field crystal model with pinning. Physical Review E, v. 78, n. 3, 1 SEP 2008. Web of Science Citations: 19.

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