Molecular Dynamics Simulation of Thermal Conductivity and Vibrational Density of States of Cadmium Telluride

Abstract

This study aims to calculate the thermal conductivity and vibrational density of states of CdTe using MD simulation. The lengths of CdTe varied from 10 nm, 20 nm, 30 nm, 40 nm, and 50 nm, with fixed width and height of 10 nm at room temperature (300 K). The results show the decrease of thermal conductivity as a function of length due to phonon-phonon interaction. The width varied from 10 nm, 20 nm, 30 nm, 40 nm, and 50 nm at room temperature (300 K) with a fixed length and height of 10 nm. Similarly, the height varied from 10 nm, 20 nm, 30 nm, 40 nm, and 50 nm with fixed length and width at room temperature (300 K).  It was found that the phonon spread less in the boundaries of the mean free path which follows the creation processes resulting to the decrease of thermal conductivity. The temperatures varied from 50 K, 75 K, 100 K, 300 K, 500 K, 700 K, 900 K, 1,000 K, and 1,365 K with fixed dimensions of 50 nm in length, 50 nm in width, and 50 nm in height. As observed, the thermal conductivity decreases with a further increase in temperature. There were four major peaks found in the vibrational density of states of cadmium telluride: ~1.3 THz and ~3.5 THz which corresponds to transverse and longitudinal acoustic modes, ~4.5 THz and ~5 THz which corresponds to transverse and longitudinal optical modes.