Pressure-dependent physical properties of cesium–niobium oxide: a comprehensive study

Abstract

Perovskites, an important class of materials, are mostly utilized in memory and spintronic devices. The thermoelectric response calculations for some perovskite oxides have been reported, but their attributes under pressure have rarely been explored. In this current study, the effects of high pressure on various properties of CsNbO₃ perovskite oxides in the cubic phase were investigated using the pseudopotential approach and Boltzmann transport theory. Specifically, the structural electronic dispersion relations, density of states, phonon properties, elasto-mechanical properties, optical constants, and thermoelectric performance of the material were analyzed. CsNbO₃ was reported to be dynamically stable through the optimization of energy against volume under ambient pressure conditions. The phonon dispersion curves of CsNbO₃ were computed at pressures ranging from 60 to 100 GPa to demonstrate its stability under these pressures. At ambient pressure, CsNbO₃ is a semiconductor with a wide direct band gap of 1.95 eV. With the increase in pressure, the band gap starts decreasing. An analysis of the imaginary part of the dielectric constant suggests that this material may be useful for sensors and optoelectronic devices. Various thermoelectric response parameters were tested for CsNbO₃ at temperatures from 50 K to 800 K, with a step size of 50 K, and pressures of 60–100 GPa. Based on the calculated power factor values and optical parameters, CsNbO₃ proved to be a potential candidate for energy harvesting applications.