Role of spin orbit coupling and electron correlation in the ground state properties of 5d electronic states

Electron correlation strength is predicted to be weak in 5d transition metal oxides and hence, various anomalous electronic properties observed in these systems are often attributed to the large spin-orbit interaction strength. Employing first principles approaches, we studied the electronic structure of Y2Ir2O7, which is insulating and exhibits ferromagnetic phase below 150 K. The results reveal breakdown of both the above paradigms. The role of spin-orbit interaction is found to be marginal in determining the ground state properties of Y2Ir2O7. A large electron correlation strength is required to derive the experimental bulk spectrum that is consistent with the bulk properties.