Molecular Dynamics Simulation of Effects of Stretching and Compressing on Thermal Conductivity of Aligned Silicon Oxygen Chains**Supported by the National Science Fund for Creative Research Groups (Grant No. 51621062).

Abstract

The effects of stretching and compressing on the thermal conductivity (TC) of silicon oxygen chain are studied by means of non-equilibrium molecular dynamics simulation. It is found that stretching can improve TC, and compressing may reduce the TC and can also increase the TC. This mechanism is explained based on the variation of phonon group velocity and the specific heat per volume with stretching and compressing. The distributions of bond angle and bond length under different normalized chain lengths are given. It is found that the bond length and bond angle in the skeleton chain would deviate from their original position. In addition, the phonon density of states (PDOSs) of silicon and oxygen atoms in the chains under different normalized chain lengths are analyzed. The overall trend is that the TC increases and the peaks of PDOSs move towards higher frequency with increasing stretch strain.