Vibrational and Thermal Properties of ZnX (X=Se, Te): Density Functional Theory (LDA and GGA) versus Experiment

TL;DR

This study uses density functional theory to calculate phonon and thermal properties of ZnSe and ZnTe, comparing results with experimental data to validate the theoretical models and analyze vibrational behaviors.

Contribution

It provides a comprehensive comparison of ab initio phonon calculations with experimental measurements for zinc chalcogenides, highlighting the accuracy of LDA and GGA methods.

Findings

Calculated phonon dispersion relations agree well with experiments.

Temperature-dependent specific heats match measured data.

Trends in phonon densities of states are discussed.

Abstract

We calculated the phonon dispersion relations of ZnX (X=Se, Te) employing ab initio techniques. These relations have been used to evaluate the temperature dependence of the respective specific heats of crystals with varied isotopic compositions. These results have been compared with mea- surements performed on crystals down to 2 K. The calculated and measured data are generally in excellent agreement with each other. Trends in the phonon dispersion relations and the correspond- ing densities of states for the zinc chalcogenide series of zincblende-type materials are discussed.