Acoustic and thermodynamic properties of cesium niobate under pressure and temperature: A DFT study

Abstract

The effect of pressure and temperature on acoustic and thermodynamic properties of cubic CsNbO3 (CNO) has been demonstrated using first principles method. The high values of velocity, impedance, and sound intensity exhibit CNO's potential acoustic applications. CNO is found thermodynamically unstable at 0 GPa, though it becomes stable at 20 GPa. The high Debye, melting temperatures, heat capacity, low thermal expansion coefficient, and thermal conductivity substantiate the compound can be used as thermal management material. The low value of the Gruneisen parameter corresponding to low anharmonicity proclaims higher lattice thermal conductivity of the material. The monotonic decline of lattice thermal conductivity with temperature is observed in CNO. The significant response of enthalpy, entropy, free energy, constant pressure heat capacity, and constant volume heat capacity with pressure and temperature have also been analyzed, which can be supportive for future investigations of CNO through experiments and theories.

Keywords

• Elastic anisotropy
• Anharmonicity
• Lattice thermal conductivity
• Dynamical stability
• Thermodynamic properties