Abstract
Sr2IrO4 is an archetypal spin-orbit-coupled Mott insulator and has been extensively studied in part because of a wide range of predicted states. Limited experimental characterization of these states thus far brings to light the extraordinary susceptibility of the physical properties to the lattice, particularly, the Ir-O-Ir bond angle. Here, we report a microscopic rotation of the IrO6 octahedra below 50 K measured by single crystal neutron diffraction. This sharp lattice anomaly provides keys to understanding the anomalous low-temperature physics and a direct confirmation of a crucial role that the Ir-O-Ir bond angle plays in determining the ground state. Indeed, as also demonstrated in this study, applied electric current readily weakens the antiferromagnetic order via the straightening of the Ir-O-Ir bond angle, highlighting that even slight change in the local structure can disproportionately affect the physical properties in the spin-orbit-coupled system.
| Original language | English |
|---|---|
| Article number | 115120 |
| Journal | Physical Review B |
| Volume | 102 |
| Issue number | 11 |
| DOIs | |
| State | Published - Sep 2020 |
Funding
We thank Dr. G. Jackeli for stimulating discussion. We acknowledge Dr. B. Hu for her help in the magnetization measurement and the technical support for the electric current measurement from J. He, G. Rucker. and H. Skorpenske. This research used resources at the Spallation Neutron Source and the High Flux Isotope Reactor, which are DOE Office of Science User Facilities operated by the Oak Ridge National Laboratory. Work at the University of Colorado was supported by the U.S. National Science Foundation via Grant No. DMR-1903888.