DFT and BoltzTrap investigations on the thermal and structural characteristics of the perovskite MgCuH3 and MgCoH3

This research investigates the structural and thermoelectrical characteristics of perovskite MgMH3 (M = Cu and Co ) using the Meta-GGA, within the framework of density functional theory (DFT), to do this, we use the BoltzTrap package implemented in the Wien2k code, we analyze the calculated total energy and atomic volume using Murnaghan equation of state along with insights into band structure and densities of states. The analysis of the band structures for MgCuH3 and MgCoH3 indicates their behavior as conductors, with the conduction band overlapping the valence band, resulting in a gap equal to 0 (ev). Furthermore, thermoelectrical properties (including electrical conductivity (sigma), thermal conductivity (kappa), merit factor (Zt), and power factor (PF)) variations across temperatures ranging from 300 to 900K, were evaluated using the BoltzTrap package, revealing intriguing aspects. The electrical conductivity (sigma) of MgCuH3 reduces, but MgCoH3 increases with rising temperature. The thermal conductivity (kappa), responsible for heat transfer, increases linearly with temperature. The Merit factor (Zt) indicates that, whereas MgCoH3 decreases between 300 and 600 K but increases between 600 and 900 K, and MgCuH3 increases with increasing temperature. The Power factor (PF) indicates that MgCoH3 (PF) decreases between 300 and 700 K but increases between 700 and 900 K and MgCuH3 increases with increasing temperature.