The effect originated from atomic vibration on thermal transport in diatomic semiconductors via ab initio molecular dynamics

Abstract

Based on the ab initio molecular dynamics (AIMD), the temperature and velocity statistics of diatomic semiconductors are proposed to be classified by atomic species. The phase differences resulting from the lattice vibrations of different atoms indicate the existence of anharmonicity at finite atomic temperatures. To explore the electronic properties further, the effect of temperature on electrostatic potential field vibrations in semiconductors is studied, and the definition of electrostatic potential oscillation (EPO) at finite atomic temperature is introduced. It is confirmed that EPO in semiconductors is caused by lattice vibrations at finite temperatures. As the temperature rises, both the intensity of EPO and the rate of EPO change in heavy and light atoms increase, which affects 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 are defined, and the results are 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 problems in semiconductor devices.