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

• Published in: Journal of Raman spectroscopy 2022-07, Vol.53 (7), p.1275-1284
• Main Authors: Oliveira, Victor V., Leite, Fábio F., Silva, Francisco W.N., Oliveira, Francisco W.C., Araujo, Francisco D.V., Menezes, Alan S., Paraguassu, W., Souza Filho, Antonio G., Viana, Bartolomeu C., Alencar, Rafael S.
• Format: Article
• Language: English
• Subjects: Anharmonicity; Bulk modulus; Compressibility; Debye temperature; Density functional theory; DFT; Gallium; gallium selenide telluride; Gallium selenides; Gruneisen parameter; Material properties; Mathematical analysis; Phase transitions; Phonons; Pressure; Pressure dependence; Process parameters; Raman spectroscopy; Red shift; Selenide; Tellurides; temperature; Temperature dependence; Thermal expansion; Thermal properties; Thermodynamic properties; Thermodynamics; Vibration mode
• ISSN: 0377-0486; 1097-4555
• DOI: 10.1002/jrs.6364

Understanding 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 A1g and E2g 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 ωA1g and ωE2g modes as a function of pressure, with the A1g modes being more compressible than E2g one, that is, ∂ωA1g∂P>∂ωE2g∂P. 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. We present a temperature‐ and pressure‐dependent Raman spectroscopy study of bulk GaSe0.5Te0.5 in order to access its thermal and mechanical properties. By combining 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.