Analysis of Cage Structured Halide Double Perovskites Cs2NaMCl6 (M = Ti, V) by Spin Polarized Calculations

The DFT and post-DFT calculations are performed to overview the structural, magneto-electronic, thermoelectric and thermo-physical behavior of Cs2NaMCl6 double perovskites. Exchange-correlation potentials are figured out by GGA, GGA + U-eff and GGA + mBJ methods to obtain more precise electromagnetic structure of these materials. The energy optimization, mechanical stability test and tolerance factor confirms the stability of these compounds in cubic Fm-3m structure. The spin polarized band structure and density of states signify the half-metallic character of materials. The unpaired electrons in the crystal field splitted d-orbitals of Ti and V are responsible for origin of half-metallic ferromagnetic nature of materials. The behavior of transport parameters of spin up and down channels further confirms half-metallic character of materials. The variation in ZT with the chemical potential demonstrates pronounced peaks on either sides of Fermi level which can attain high values close to unity. The 100% spin polarization and high value of ZT convey that Cs2NaMCl6 (M = Ti, V) double perovskites could find applications in spintronic and thermoelectric technologies. (C) 2020 Elsevier B.V. All rights reserved.