Observation of the coherent quasiparticle states in SrRu_1-xIr_xO₃ films via polarization-dependent soft X-ray absorption spectroscopy

The electronic structures of SrRu 1 − xIr xO 3 films ( 0 ≤ x ≤ 1) have been investigated by employing polarization-dependent soft X-ray absorption spectroscopy. In SrIrO 3, the coherent quasi-particle peak at the Fermi level ( E F) is clearly observed, reflecting the spin-orbit-coupled correlated metallic nature of SrIrO 3. X-ray linear dichroism signals for x = 0 and x = 1 are negligibly weak, demonstrating the pseudo-cubic structure for SrRuO 3 and the strong spin-orbit coupling in SrIrO 3. In contrast, finite linear dichroism is observed for the intermediate x regime, indicating that the narrow d x z ↓ and d y z ↓ bands close to E F are occupied less than the wide d x y ↓ band due to the enhanced in-plane hopping.