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Ab Initio Molecular Dynamics Study of Structural and Transport
Properties of Liquid Germanium

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R. V. Kulkarni, W. G. Aulbur, and D. Stroud,
Department of Physics, The Ohio State University,
Columbus, Ohio 43210

We describe the results of ab initio molecular dynamics simulations
of liquid Ge at five temperatures ranging from 1250 K to 2000 K. The
electronic structure is calculated using the local density approximation and
generalized norm-conserving pseudopotentials. The
calculations yield the pair correlation function, the static structure factor,
the bond angle distribution function, the electronic density of states, the
atomic self-diffusion coefficient and finally the a. c. conductivity.
Near melting, the structure factor
has the experimentally observed shoulder on the
high-k side of the principal peak, which becomes progressively less
distinct at higher temperatures. The bond angle distribution function
indicates the persistence of covalent bonding for shorter bond lengths in
the liquid state. The electronic density of states is metallic at all the
temperatures with a pseudogap at a binding energy of 4.6 eV. The diffusion
constant shows a sharp rise between 1250 K and
1500 K 1.2 X 10^(-4) cm^2 s^(-1) to
2.0 X 10^(-4) cm^2 s^(-1)), and increases less rapidly
at higher temperatures, to only 2.3 X 10^(-4) cm^2 s^(-1) at
2000 K.
PACS Nos.: 61.20.Jz, 61.20.Gy, G1.20.Lc, 61.25.Mv