Cooperative effects of lattice and spin-orbit coupling on the electronic structure of orthorhombic SrIrO₃

Orthorhombic SrIrO3 subjected to strain shows tunable transport properties. With underlying symmetry remaining invariant, these properties are associated with IrO6 octahedral tilting. Adopting first-principles methods, the effects of crystal field, spin-orbit coupling (SOC), and Coulomb correlations, on comparable interaction length scales, are discussed. While tilting induces a t(2g) - e(g) crystal-field splitting and band narrowing, SOC induces a partial splitting of the J(eff) bands rendering SrIrO3 a semi-metallic ground state. The SOC enhanced hybridization of Ir-O orbitals serves as an explanation as to why the critical Hubbard correlation strength increases with increasing SOC strength in SrIrO3 to induce an insulating phase.