The effect of atomic vibration on thermal transport in diatomic semiconductors investigated via ab initio molecular dynamics

Abstract

Based on the ab initio molecular dynamics (AIMD), the temperature and velocity statistics of diatomic semiconductors were proposed to be classified by atomic species. The phase differences resulting from lattice vibrations of different atoms indicated the presence of anharmonicity at finite atomic temperatures. To further explore the electronic properties, the effect of temperature on electrostatic potential field vibrations in semiconductors was studied, and the concept of electrostatic potential oscillation (EPO) at finite atomic temperature was introduced. It was confirmed that EPO in semiconductors was driven by lattice vibrations at finite temperatures. As the temperature increased, both the intensity of EPO and the rate of EPO change in heavy and light atoms increased, influencing electron thermal transport. To characterize the uncertainties in atomic lattice vibrations and EPO, the entropies of atomic EPO, atomic velocity of EPO (VEPO), atomic temperature, and atomic velocity were defined, with results consistent with the principle of entropy increase. This study not only aids in understanding the fundamental physical picture of electronic properties in semiconductors at finite temperatures but also provides a method for describing their uncertainties. The new theoretical concepts and statistical methods presented here can advance the understanding of electron thermal transport issues in semiconductor devices.