Oxygen states in La- and Rh-doped Sr 2 IrO 4 probed by angle-resolved photoemission and O K edge RIXS

V. Ilakovac (1, 2) , A. Louat (3) , A. Nicolaou (4) , J.-P. Rueff (4, 1) , Yves Joly (5) , V. Brouet (3)

1 LCPMR - Laboratoire de Chimie Physique - Matière et Rayonnement
2 UCP - Université de Cergy Pontoise
3 LPS - Laboratoire de Physique des Solides
4 SSOLEIL - Synchrotron SOLEIL
5 NEEL - SIN - Surfaces, Interfaces et Nanostructures

Iridates are often viewed as an equivalent of cuprates with strong spin-orbit coupling. As such, they offer a new way to study the physics of Mott insulators. The hybridization with oxygen is, of course, essential in both compounds and may play a crucial role in the doping process. It could be quite different in the two families, iridates being 5d transition metals with different orbital geometries. But this difference has not been studied in detail so far. We present a combined angle-resolved photoemission spectrescopy and O K-edge resonant inelastic x-ray scattering study to document this aspect in Sr 2 IrO 4 , pure and doped with 4% La and 15% Rh. We evidence different charge transfer excitations and distinguish those associated with apical or in-plane oxygens. We observe a specific evolution of one excitation upon Rh doping, which suggests a more itinerant nature of the holes related to the apical oxygen. This gives information on the way doping proceeds in iridates.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

V. Ilakovac, A. Louat, A. Nicolaou, J.-P. Rueff, Yves Joly, et al.. Oxygen states in La- and Rh-doped Sr 2 IrO 4 probed by angle-resolved photoemission and O K edge RIXS. Physical Review B, 2019, 99 (3), pp.035149. ⟨10.1103/PhysRevB.99.035149⟩. ⟨hal-01996366⟩