Parameter space exploration reveals interesting Mn-doped SrTiO3 structures

Abstract

The rich chemistry of the SrTiO₃ is often modified, intentionally or unintentionally, through the inclusion of defects and dopants. Much computational effort using periodic boundary DFT has been dedicated towards understanding how these observed properties arise from the disordered perovskite structure, but the range of possible defect chemistries arising from different computational modeling choices has not been thoroughly explored. In this study, we calculate the geometric and electronic properties for a systematic range of supercells, from approximately 40 atoms to approximately 320 atoms, with each atomic vacancy and doped with Mn ions to isolate the contribution of supercell size to predicted properties. Our thorough analysis of the electronic and geometric structure of each defected supercell shows high variability, illustrating the need to map the parameter space in order to achieve a comprehensive model of disordered perovskites. Our results additionally reveal fundamental insights into dopant chemistry in SrTiO₃, and we report new potential geometric and electronic structures for Mn dopants that can be used to justify and guide additional experimental investigation into this complex material.