Pressure dependence of the electronic, optical, thermoelectric, thermodynamic properties of CsVO3: first-principles study

Abstract

ABSTRACT We have studied hydrostatic pressure dependence of the electronic, optical, thermodynamic and thermoelectric properties of CsVO3 via first principles calculations. In addition, temperature dependence of the thermoelectric and thermal parameters was investigated. The calculated equilibrium structural parameters are in excellent agreement with the available experimental counterparts. The calculated phonon-band dispersion curve confirms the dynamic stability of CsVO3 compound in its ground-state. Analysis of the energy band dispersion calculated within the TB-mBJ potential reveals that CsVO3 is a direct bandgap semiconductor with a fundamental bandgap of 3.14 eV. It is found that the bandgap increases with increasing pressure. Analysis of the DOS diagrams and charge density topology shows that the V-O bond is partially covalent and the Cs-O bond is predominantly ionic in nature. Frequency-dependent linear macroscopic optical coefficients, namely absorption coefficient, refractive index, extinction coefficient, reflectivity and optical conductivity, were deduced from the calculated real and imaginary parts of the complex dielectric function under hydrostatic pressure effect. The semi-classic Boltzmann transport theory was used to explore pressure and temperature dependencies of the thermoelectric properties. Pressure and temperature dependencies of the thermal parameters, viz., isochore and isobar heat capacities, lattice thermal conductivity, volume thermal expansion coefficient and Debye temperature, were explored through the quasi-harmonic Debye model.