Ab-Initio Investigation of Pristine and Intrinsic Vacancy Defect-containing A3SnO and A3PbO (A: Ca, Sr and Ba) Inverse Perovskites

Abstract

The A3SnO and A3PbO (A: Ca, Sr and Ba) inverse perovskite oxides have gained immense research attention as they exhibit physical properties suitable for thermoelectric, superconducting and magnetic devices. The emergence of stoichiometry dependent stable ferromagnetism in these inverse perovskites has recently made these materials potential candidates for utilization in spintronic and quantum computing devices. In the present work, DFT based first principles total energy calculations have been employed using the full-potential linearized augmented plane-wave method to explore the electronic, magnetic and thermodynamic properties of pristine and intrinsic vacancy defect containing A3SnO and A3PbO (A: Ca, Sr and Ba) compounds. The electronic structures of these compounds are computed with the inclusion of spin orbit coupling interactions which plays an important role in topological nature of these compounds. Furthermore, the spin-polarization calculations have been carried out to investigate the impact of vacancy defects on magnetic and electronic properties of these inverse perovskites. The thermodynamic stability analysis indicated that these materials can be synthesized under Ca/Sr/Ba rich and Sn/Pb intermediate-rich conditions. Moreover, the defect formation energies revealed that Ca/Ba/Sr vacancies are the most stable form of vacancy defect under oxidation (O-rich) conditions, while O and Sn/Pb vacancies are found to have stable under reduction (O-poor) and Sn/Pb-poor conditions, respectively. Our calculations reveal that charge neutral Sn or O vacancies can give rise to stable ferromagnetism in non-stoichiometric A3SnO and A3PbO (A: Ca, Sr and Ba) compounds.