Molecular Dynamics Study on Structural Relaxation Processes in Amorphous Germanium

Abstract

The structural relaxation of amorphous germanium was examined by molecular dynamics simulations based on the empirical Tersoff interatomic potential. Although the Tersoff potential overestimated both the melting and glass transition temperatures, it was able to reproduce the structural relaxation behavior. The potential energy decreases with thermal annealing below the glass transition temperature, but occasionally increases during structural relaxation. The mean square displacement of atoms also increases in these periods. These changes were attributed to cooperative atomic motion during the structural relaxation. Atomic trajectories revealed that structural changes are induced by spatially-and temporally-inhomogeneous atomic motions: atomically mobile and immobile regions coexist during structural relaxation.

Cluster-Assisted Mesoplasma Chemical Vapor Deposition for Fast Epitaxial Growth of SiGe/Si Heterostructures: A Molecular Dynamics Simulation Study

“…Although this potential has a shortcoming in that it overestimates the melting temperatures of pure Si and Ge [26,27], it provides accurate cross-potential parameters that could be used to model the binary Si-Ge system. In addition, the availability of nucleation and growth for mixed SiGe clusters has been verified by Nordlund et al [28,29], and they have demonstrated that the Tersoff potential can effectively reproduce the structural properties of amorphous SiGe clusters.…”

Impact of supercooled liquid structures on the crystallization processes of amorphous Ge

“…It is also known that this potential can reproduce well-disordered structures, such as amorphous and liquid, and pressure-induced polyamorphism of group-IV elements. [28][29][30][31][32] The Ge atoms were initially arranged to take a diamondtype structure with a lattice parameter of 0.566 nm, which is consistent with the density of crystalline Ge. Here, the x, y, and z directions are defined as the [100], [010] and [001] directions of the diamond structure, respectively.…”