Temperature‐ and pressure‐dependent phonon dynamics properties of gallium selenide telluride

Abstract

AbstractUnderstanding the thermodynamic properties of materials is a fundamental issue in physics, and its knowledge is crucial for targeting a specific material for possible applications. In this work, we report a temperature‐ and pressure‐dependent Raman study of bulk GaSe0.5Te0.5 alloy, besides their relevant thermodynamic parameters. Our results show a nonlinear redshift for the and vibrational modes as the temperature increases in the temperature range from 10 to 748 K. Such behavior is well described by considering both thermal expansion and phonon–phonon coupling contributions. By combining density functional theory (DFT) calculations and Raman spectroscopy experiments, the anharmonic constants relative to the three‐ and four‐phonon decay processes, mode‐Grüneisen parameters, Debye temperature, thermal expansion coefficient, and bulk modulus were estimated for GaSe0.5Te0.5 alloy. Furthermore, the high‐pressure measurements and DFT calculations, performed in the pressure range from 0 to 26.4 GPa, show a quadratic trend for the and modes as a function of pressure, with the modes being more compressible than one, that is, . No structural phase transition is observed until the maximum pressure reached in the experiment. This study took a step forward in the understanding of mechanical and thermal properties related to GaSe0.5Te0.5 alloy, whose determined parameters are important for designing new applications.