Molecular-dynamics approach for determining the vacancy heat of transport

    Authors

    Z. McDargh;P. K. Schelling

    Comments

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    Abbreviated Journal Title

    Comput. Mater. Sci.

    Keywords

    Thermotransport; Soret effect; Thermal diffusion; Heat of transport; THERMAL-DIFFUSION; SOLIDS; Materials Science, Multidisciplinary

    Abstract

    We develop an approach for using equilibrium and nonequilibrium molecular-dynamics simulations to determine the heat of transport of a vacancy in a Lennard-Jones fcc crystal. The approach depends on computing the entropy and internal energy changes that accompany the hopping of a vacancy either parallel or antiparallel to a temperature gradient. We find that the internal energy, expressed in terms of the vacancy formation energy, is essentially unchanged during vacancy hops. However, we show that entropy is generated during vacancy hops, indicating the presence of dissipative processes. We show theoretically how the computation of the entropy generation is directly related to the reduced heat of transport. From an estimate of the enthalpy of vacancy formation, we determine the heat of transport, which is found to be positive in contradiction to previously-published results using a different method. The heat of transport we predict is quite close to the enthalpy of vacancy formation. (C) 2011 Elsevier B.V. All rights reserved.

    Journal Title

    Computational Materials Science

    Volume

    50

    Issue/Number

    8

    Publication Date

    1-1-2011

    Document Type

    Article

    Language

    English

    First Page

    2363

    Last Page

    2370

    WOS Identifier

    WOS:000291283700009

    ISSN

    0927-0256

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