First-principles study of the thermodynamic properties of the bulk cubic compound InTe at high temperature and pressure

We performed a first-principles study of the structural and dynamical properties of the bulk cubic InTe compound, and subsequently presented a detailed analysis of its thermodynamic properties under high-temperature and high-pressure conditions. The structural parameters were optimized using Density Functional Theory (DFT) within the full-potential linearized augmented-plane wave (FP-LAPW) method under the Local Density Approximation (LDA). The dynamical stability was confirmed by the absence of imaginary frequencies in the phonon dispersion curves and through ab initio molecular dynamics (AIMD) simulations. Thermodynamic properties, including unit cell volume, bulk modulus, Gibbs free energy, Debye temperature, isochoric and isobaric heat capacities, thermal expansion coefficient, and entropy, were computed using the quasi-harmonic Debye model implemented in the Gibbs2 code, covering a temperature range from 0 to 800 K and a pressure range from 0 to 8 GPa. The results for the Gibbs free energy reveal that bulk InTe exhibits greater thermodynamic stability (lower Gibbs free energy) at high temperatures and low pressures. Furthermore, the findings highlight that pressure significantly influences the bulk modulus, unit cell volume, and thermal expansion coefficient, while temperature notably affects the heat capacity and entropy values. The results related to the Grüneisen parameter indicate that the anharmonic stability of cubic InTe is governed by a competition between the effects of temperature and pressure: temperature tends to mitigate anharmonicity, while pressure enhances it, thereby contributing to the stabilization of the material under high compression conditions. The cubic InTe compound, owing to its thermodynamic stability at high temperatures and low pressures, as well as its remarkable thermal properties, can be considered for demanding industrial applications. Its characteristics might make it a suitable material for extreme environments, such as high-pressure sensors, optoelectronic devices, thermal management systems, and advanced energy technologies.