Title

Analysis of simulation methodology for calculation of the heat of transport for vacancy thermodiffusion

Authors

Authors

W. C. Tucker;P. K. Schelling

Comments

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Abbreviated Journal Title

J. Appl. Phys.

Keywords

SOLID ARGON; GOLD; DIFFUSION; Physics, Applied

Abstract

Computation of the heat of transport Q*(a) in monatomic crystalline solids is investigated using the methodology first developed by Gillan [J. Phys. C: Solid State Phys. 11, 4469 (1978)] and further developed by Grout and coworkers [Philos. Mag. Lett. 74, 217 (1996)], referred to as the Grout-Gillan method. In the case of pair potentials, the hopping of a vacancy results in a heat wave that persists for up to 10 ps, consistent with previous studies. This leads to generally positive values for Q*(a) which can be quite large and are strongly dependent on the specific details of the pair potential. By contrast, when the interactions are described using the embedded atom model, there is no evidence of a heat wave, and Q*(a) is found to be negative. This demonstrates that the dynamics of vacancy hopping depends strongly on the details of the empirical potential. However, the results obtained here are in strong disagreement with experiment. Arguments are presented which demonstrate that there is a fundamental error made in the Grout-Gillan method due to the fact that the ensemble of states only includes successful atom hops and hence does not represent an equilibrium ensemble. This places the interpretation of the quantity computed in the Grout-Gillan method as the heat of transport in doubt. It is demonstrated that trajectories which do not yield hopping events are nevertheless relevant to computation of the heat of transport Q*(a). (C) 2014 AIP Publishing LLC.

Journal Title

Journal of Applied Physics

Volume

116

Issue/Number

2

Publication Date

1-1-2014

Document Type

Article

Language

English

First Page

10

WOS Identifier

WOS:000340267600016

ISSN

0021-8979

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