Structural, electronic, optical and thermoelectric investigations of antiperovskites A3SnO (A = Ca, Sr, Ba) using density functional theory

Density functional theory study of the structural, electrical, optical and thermoelectric behaviors of very less investigated anti-perovskites A(3)SnO (A = Ca, Sr, Ba) is performed with FP-LAPW technique. The A(3)SnO exhibit narrow direct band gap, in contrast to the wide indirect band gap of the respective perovskites. Hence, indirect to direct band gap transformation can be realized by the structural transition from perovskite to anti-perovskite. The p-p hybridization between A and O states result in the covalent bonding. The transparency and maximum reflectivity to the certain energies, and the verification of the Penn's model indicate potential optical device applications. Thermoelectric behaviors computed within 200-800 K depict that Ca3SnO exhibits good thermoelectric performance than Ba3SnO and Sr3SnO, and all three operate at their best at 800 K suggesting high temperature thermoelectric device applications.