From Jeff=1/2 insulator to p-wave superconductor in single-crystal Sr2Ir1-xRuxO4 (0 < x< 1)

TL;DR

This study explores how Ru doping in Sr2IrO4 alters its structure, magnetic, and electronic properties, leading to a phase transition from an insulator to a metal and providing insights into the interplay of spin-orbit coupling and doping.

Contribution

It demonstrates how Ru substitution modulates spin-orbit coupling and induces a structural and electronic phase transition in Sr2IrO4, revealing new pathways to tune its properties.

Findings

Ru doping induces a structural phase transition near x=0.50

A transition from antiferromagnetic insulator to paramagnetic metal occurs

Comparison with Rh doping highlights key similarities and differences

Abstract

Sr2IrO4 is a magnetic insulator assisted by strong spin-orbit coupling (SOC) whereas the Sr2RuO4 is a p-wave superconductor. The contrasting ground states have been shown to result from the critical role of the strong SOC in the iridate. Our investigation of structural, transport, and magnetic properties reveals that substituting 4d Ru4+ (4d4) ions for 5d Ir4+(5d5) ions in Sr2IrO4 directly adds holes to the t2g bands, reduces the SOC and thus rebalances the competing energies in single-crystal Sr2Ir1-xRuxO4. A profound effect of Ru doping driving a rich phase diagram is a structural phase transition from a distorted I41/acd to a more ideal I4/mmm tetragonal structure near x=0.50 that accompanies a phase transition from an antiferromagnetic-insulating state to a paramagnetic-metal state. We also make a comparison drawn with Rh doped Sr2IrO4, highlighting important similarities and differences.