Electrical control of structural and physical properties is a long-sought, but elusive goal of contemporary science and technology. We demonstrate that a combination of strong spin-orbit interactions (SOI) and a canted antiferromagnetic Mott state is sufficient to attain that goal. The antiferromagnetic insulator Sr2IrO4 provides a model system in which strong SOI lock canted Ir magnetic moments to IrO6 octahedra, causing them to rigidly rotate together. A novel coupling between an applied electrical current and the canting angle reduces the Néel temperature and drives a large, nonlinear lattice expansion that closely tracks the magnetization, increases the electron mobility, and precipitates a unique resistive switching effect. Our observations open new avenues for understanding fundamental physics driven by strong SOI in condensed matter, and provide a new paradigm for functional materials and devices.
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This work was supported by the National Science Foundation via Grants No. DMR-1712101 (University of Colorado) and No. DMR-1506979 (L. E. D.), and by Department of Energy, Office of Basic Energy Science, Materials Science through the award DEFG02-84ER45872 (P. S. R.).
Cao, Gang; Terzic, Jasminka; Zhao, H. D.; Zheng, H.; De Long, Lance E.; and Riseborough, Peter S., "Electrical Control of Structural and Physical Properties via Strong Spin-Orbit Interactions in Sr2IrO4" (2018). Physics and Astronomy Faculty Publications. 581.