DFT calculations of opto-electronic, mechanical, thermodynamic, and transport properties of XCeO3 (X = Mg, Ca, and Ba) perovskite

Abstract

We report structural, electronic, mechanical, optical, thermodynamic, and thermoelectric properties of XCeO3 (X = Mg, Ca, and Ba) perovskite using density functional theory as inculcated in WIEN2K code. In the structural perspective these perovskites are found crystalized in their cubic phase Pm-3 m (221). The electronic profiles show semiconducting nature of all inspected materials. We have included various potentials like LDA, GGA-PBE, mBJ, mBJ + SOC and HSE06 to estimate energy band gap of the considered materials. We have estimated band gap of 2.266, 2.619, 2.439 eV for the MgCeO3, CaCeO3 and BaCeO3 perovskites. The mechanical and dynamical stabilities of these compounds are assured by calculating mechanical properties and phonon band structure, respectively. Further, the optical parameters such as reflectivity, absorption coefficient, dielectric function, optical conductivity and energy loss are examined corresponding to photon energy within the energy range of 0 to 13 eV. These materials are active in UV-region and can be used as UV-absorber. Furthermore, thermoelectric properties are examined by evaluating Seebeck coefficient, thermal and electronic conductivities, figure of merit and power factor. Thermoelectric efficiency shows increasing behavior corresponding to temperature. Materials show good thermoelectric efficiency at 1200 K equivalent to 0.64, 0.66, 0.7 for MgCeO3, CaCeO3, BaCeO3, respectively. The thermodynamic stability of XCeO3 is ensured by studying the behaviour of volume, bulk modulus, entropy, heat capacity, thermal expansion coefficient, Gr u¨ neisen constant and Debye temperature corresponding to temperature and pressure. The novelty in these materials is found for their suggestive applications as UV absorber, thermoelectric power generators, temperature resistant materials.