Analysis of simulation methodology for calculation of the heat of transport for vacancy thermodiffusion
Abstract
Computation of the heat of transport Q{sub a}{sup *} 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 GroutGillan 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{sub a}{sup *} 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{sub a}{sup *} 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 GroutGillan method due to the fact that the ensemble of states only includes successful atom hops and hence does not represent an equilibrium ensemble. This placesmore »
 Authors:
 Advanced Material Processing and Analysis Center and Department of Physics, University of Central Florida, 4000 Central Florida Blvd., Orlando, Florida 32816 (United States)
 Publication Date:
 OSTI Identifier:
 22308966
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ATOMS; CALCULATION METHODS; EQUILIBRIUM; HEAT; HEAT TRANSFER; INTERACTIONS; SIMULATION; SOLIDS; THERMAL DIFFUSION; TRAJECTORIES; VACANCIES
Citation Formats
Tucker, William C., and Schelling, Patrick K., Email: patrick.schelling@ucf.edu. Analysis of simulation methodology for calculation of the heat of transport for vacancy thermodiffusion. United States: N. p., 2014.
Web. doi:10.1063/1.4887121.
Tucker, William C., & Schelling, Patrick K., Email: patrick.schelling@ucf.edu. Analysis of simulation methodology for calculation of the heat of transport for vacancy thermodiffusion. United States. doi:10.1063/1.4887121.
Tucker, William C., and Schelling, Patrick K., Email: patrick.schelling@ucf.edu. Mon .
"Analysis of simulation methodology for calculation of the heat of transport for vacancy thermodiffusion". United States.
doi:10.1063/1.4887121.
@article{osti_22308966,
title = {Analysis of simulation methodology for calculation of the heat of transport for vacancy thermodiffusion},
author = {Tucker, William C. and Schelling, Patrick K., Email: patrick.schelling@ucf.edu},
abstractNote = {Computation of the heat of transport Q{sub a}{sup *} 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 GroutGillan 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{sub a}{sup *} 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{sub a}{sup *} 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 GroutGillan 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 GroutGillan 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{sub a}{sup *}.},
doi = {10.1063/1.4887121},
journal = {Journal of Applied Physics},
number = 2,
volume = 116,
place = {United States},
year = {Mon Jul 14 00:00:00 EDT 2014},
month = {Mon Jul 14 00:00:00 EDT 2014}
}

We apply the recently developed constraineddynamics method to elucidate the thermodiffusion of vacancies in a singlecomponent material. The derivation and assumptions used in the method are clearly explained. Next, the method is applied to compute the reduced heat of transport Q{sub v}{sup *}−h{sub fv} for vacancies in a singlecomponent material. Results from simulations using three different Morse potentials, with one providing an approximate description of Au, and an embeddedatom model potential for Ni are presented. It is found that the reduced heat of transport Q{sub v}{sup *}−h{sub fv} may take either positive or negative values depending on the potential parametersmore »

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