Unidirectional spin density wave state in metallic (Sr1-xLax)2IrO4

TL;DR

This paper reports the discovery of a unidirectional spin density wave state in electron-doped Sr2IrO4, revealing magnetic similarities with hole-doped cuprates and suggesting common competing electronic phases in these correlated materials.

Contribution

It uncovers a spin density wave state in electron-doped Sr2IrO4, establishing a magnetic parallel with cuprates and advancing understanding of its electronic phase diagram.

Findings

Identification of incommensurate magnetic order in Sr2IrO4

Magnetic similarity between electron-doped Sr2IrO4 and hole-doped La2CuO4

Support for common competing phases in Mott insulators

Abstract

Materials that exhibit both strong spin orbit coupling and electron correlation effects are predicted to host numerous new electronic states. One prominent example is the Jeff =1/2 Mott state in Sr2IrO4, where introducing carriers is predicted to manifest high temperature superconductivity analogous to the S=1/2 Mott state of La2CuO4. While bulk superconductivity currently remains elusive, anomalous quasi-particle behaviors paralleling those in the cuprates such as pseudogap formation and the formation of a d-wave gap are observed upon electron-doping Sr2IrO4. Here we establish a magnetic parallel between electron-doped Sr2IrO4 and hole-doped La2CuO4 by unveiling a spin density wave state in electron-doped Sr2IrO4. Our magnetic resonant x-ray scattering data reveal the presence of an incommensurate magnetic state reminiscent of the diagonal spin density wave state observed in the monolayer cuprate (La1-xSrx)2CuO4. This link supports the conjecture that the quenched Mott phases in electron-doped Sr2IrO4 and hole-doped La2CuO4 support common competing electronic phases.