Interface-engineered hole doping in Sr2IrO4/LaNiO3 heterostructure

P Shafer,E Arenholz,Fangdi Wen,Lin Gu,J W Freeland,Qinghua Zhang,M Kareev,Yanwei Cao,J Chakhalian,A T N’Diaye,Xiaoran Liu,B Pal

doi:10.1088/1367-2630/ab452c

Abstract

The relativistic Mott insulator Sr2IrO4 driven by large spin–orbit interaction is known for the 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.

Highlights

Transition metal oxides (TMOs) with a partially filled d-shell often host strongly correlated carriers and exhibit unique physical properties due to the intertwined lattice, charge, orbital and spin degrees of freedom.[1]
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
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

Summary

Introduction

Transition metal oxides (TMOs) with a partially filled d-shell often host strongly correlated carriers and exhibit unique physical properties due to the intertwined lattice, charge, orbital and spin degrees of freedom.[1]. As the outcome of the competing interactions dominated by SOC, a large number of unusual quantum states including topological insulators[2], quantum spin liquids [3], Weyl semimetals [4], and Kitaev materials[5] have been recently predicted. In this category, Sr2IrO4 is one of the prototypical examples of materials known as the relativistic Mott insulators. [8, 9] Resonant inelastic x-ray scattering experiments reveales that the magnetic excitations of Sr2IrO4 on the square lattice can be well described within an antiferromagnetic Heisenberg model[10] akin to the parent compounds of cuprates. The heterostructure remains insulating, we found that the transport behavior is no longer described by the Mott variable range hopping model, but by the Efros-Shklovskii model

EXPERIMENTAL SECTION

Findings

CONCLUSION