Interface-engineered hole doping in Sr2IrO4/LaNiO3 heterostructure

Abstract

The relativistic Mott insulator Sr _2 IrO _4 driven by large spin–orbit interaction is known for the ${J}_{\mathrm{eff}}=1/2$ antiferromagnetic state which closely resembles the electronic structure of parent compounds of superconducting cuprates. Here, we report the realization of hole-doped Sr _2 IrO _4 by means of interfacial charge transfer in Sr _2 IrO _4 /LaNiO _3 heterostructures. X-ray photoelectron spectroscopy on Ir 4 f edge along with the x-ray absorption spectroscopy at Ni L _2 edge confirmed that 5 d electrons from Ir sites are transferred onto Ni sites, leading to markedly electronic reconstruction at the interface. Although the Sr _2 IrO _4 /LaNiO _3 heterostructure remains non-metallic, we reveal that the transport behavior is no longer described by the Mott variable range hopping mode, but by the Efros–Shklovskii model. These findings highlight a powerful utility of interfaces to realize emerging electronic states of the Ruddlesden–Popper phases of Ir-based oxides.

Keywords

• complex oxide heterostructure
• x-ray absorption spectroscopy
• layered-Iridates