Spin-orbit-enhanced magnetic surface second-harmonic generation in Sr₂IrO₄
Abstract
An anomalous optical second-harmonic generation (SHG) signal was previously reported in Sr₂IrO₄ and attributed to a hidden odd-parity bulk magnetic state. Here we investigate the origin of this SHG signal using a combination of bulk magnetic susceptibility, magnetic-field-dependent SHG rotational anisotropy, and overlapping wide-field SHG imaging and atomic force microscopy measurements. We find that the anomalous SHG signal exhibits a twofold rotational symmetry as a function of in-plane magnetic field orientation that is associated with a crystallographic distortion. We also show a change in SHG signal across step edges that tracks the bulk antiferromagnetic stacking pattern. While we do not rule out the existence of hidden order in Sr₂IrO₄, our results altogether show that the anomalous SHG signal in parent Sr₂IrO₄ originates instead from a surface-magnetization-induced electric-dipole process that is enhanced by strong spin-orbit coupling.
Additional Information
© 2020 American Physical Society. (Received 26 July 2020; revised 30 October 2020; accepted 2 November 2020; published 13 November 2020) We acknowledge helpful conversations with Gang Cao, Nicholas Laurita, Sergio Di Matteo, Mike Norman, Alon Ron, Chandra Varma, and Liuyan Zhao. This work is supported by an ARO PECASE award W911NF-17-1-0204. D.H. also acknowledges support for instrumentation from the David and Lucile Packard Foundation and from the Institute for Quantum Information and Matter (IQIM), an NSF Physics Frontiers Center (PHY-1733907). K.L.S. acknowledges a Caltech Prize Postdoctoral Fellowship. A.d.l.T. acknowledges support from the Swiss National Science Foundation through an Early Postdoc Mobility Fellowship (P2GEP2_165044). S.D.W., E.Z., and Z.P. acknowledge support from ARO Award No. W911NF-16-1-0361. R.P. acknowledges support from IQIM.Attached Files
Published - PhysRevB.102.201113.pdf
Accepted Version - 2011.11662.pdf
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Additional details
- Alternative title
- Spin-orbit-enhanced magnetic surface second-harmonic generation in Sr2IrO4
- Eprint ID
- 106666
- Resolver ID
- CaltechAUTHORS:20201113-100152383
- W911NF-17-1-0204
- Army Research Office (ARO)
- David and Lucile Packard Foundation
- Institute for Quantum Information and Matter (IQIM)
- PHY-1733907
- NSF
- Robert A. Millikan Fellowship
- P2GEP2_165044
- Swiss National Science Foundation (SNSF)
- W911NF-16-1-0361
- Army Research Office (ARO)
- Created
-
2020-11-16Created from EPrint's datestamp field
- Updated
-
2023-03-15Created from EPrint's last_modified field
- Caltech groups
- Institute for Quantum Information and Matter