ABSTRACT

In this paper we extend the quasi-continuum method to study equilibrium
properties of defects at finite temperatures. We present a derivation of an
effective energy function to perform Monte Carlo simulations in a mixed
atomistic and continuum setting. It is shown that the free energy minimization
technique can be easily incorporated into the quasi-continuum framework,
permitting a reduction of the full set of atomistic degrees of freedom even in
the finite temperature setting. The validity of the proposed methods is
demonstrated by computing the thermal expansion and the temperature dependence
of the elastic moduli for Cu. We also employ the quasi-continuum free energy
minimization method to study the finite temperature structure of a dislocation
core in Al.