Interface-engineered hole doping in Sr2IrO4/LaNiO3 heterostructure

TL;DR

This study demonstrates interface-induced hole doping in Sr2IrO4/LaNiO3 heterostructures, leading to electronic reconstruction and altered transport behavior, showcasing the potential of interfaces to engineer novel electronic states in Ir-based oxides.

Contribution

It introduces a method of hole doping Sr2IrO4 via interfacial charge transfer in heterostructures, revealing new electronic states and transport properties.

Findings

Ir electrons transfer to Ni sites at the interface

Transport behavior shifts from Mott variable range hopping to Efros-Shklovskii model

Heterostructure remains non-metallic despite doping

Abstract

The relativistic Mott insulator Sr2IrO4 driven by large spin-orbit interaction is known for the Jeff = 1/2 antiferromagnetic state which closely resembles the electronic structure of parent compounds of superconducting cuprates. Here, we report the realization of hole-doped Sr2IrO4 by means of interfacial charge transfer in Sr2IrO4/LaNiO3 heterostructures. X-ray photoelectron spectroscopy on Ir 4f edge along with the X-ray absorption spectroscopy at Ni L2 edge confirmed that 5d electrons from Ir sites are transferred onto Ni sites, leading to markedly electronic reconstruction at the interface. Although the Sr2IrO4/LaNiO3 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.