Dynamic structure factor of liquid and amorphous Ge from ab initio simulations

Article

关键词: ABINITIO MOLECULAR-DYNAMICS;    TOPOLOGICALLY DISORDERED-SYSTEMS;    TOTAL-ENERGY CALCULATIONS;    WAVE BASIS-SET;    FIRST-PRINCIPLES;    ATOMIC-STRUCTURE;    SILICON;    GERMANIUM;    METALS;    GAAS;   

DOI  :  10.1103/PhysRevB.67.104205

来源: SCIE

【 摘 要 】

We calculate the dynamic structure factor S(k,omega) of liquid Ge (l-Ge) at temperature T = 1250 K, and of amorphous Ge (a-Ge) at T = 300 K, using ab initio molecular dynamics. The electronic energy is computed using density-functional theory, primarily in the generalized gradient approximation, together with a plane-wave representation of the wave functions and ultrasoft pseudopotentials. We use a 64-atom cell with periodic boundary conditions, and calculate averages over runs of up to about 16 ps. The calculated liquid S(k,omega) agrees qualitatively with that obtained by Hosokawa [Phys. Rev. B 63, 134205 (2001)] using inelastic x-ray scattering. In a-Ge, we find that the calculated S(k,omega) is in qualitative agreement with that obtained experimentally by Maley [Phys. Rev. Lett. 56, 1720 (1986)]. Our results suggest that the ab initio approach is sufficient to allow approximate calculations of S(k,omega) in both liquid and amorphous materials.

【 授权许可】

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