Structural Distortion-Induced Magnetoelastic Locking in Sr_2IrO_4 Revealed through Nonlinear Optical Harmonic Generation

Torchinsky, D. H. and Chu, H. and Zhao, L. and Perkins, N. B. and Sizyuk, Y. and Qi, T. and Cao, G. and Hsieh, D. (2015) Structural Distortion-Induced Magnetoelastic Locking in Sr_2IrO_4 Revealed through Nonlinear Optical Harmonic Generation. Physical Review Letters, 114 (9). Art. No. 096404. ISSN 0031-9007. doi:10.1103/PhysRevLett.114.096404. https://resolver.caltech.edu/CaltechAUTHORS:20141117-101456748

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Abstract

We report a global structural distortion in Sr2IrO4 using spatially resolved optical second and third harmonic generation rotational anisotropy measurements. A symmetry lowering from an I4_1/acd to I4_1/a space group is observed both above and below the Néel temperature that arises from a staggered tetragonal distortion of the oxygen octahedra. By studying an effective superexchange Hamiltonian that accounts for this lowered symmetry, we find that perfect locking between the octahedral rotation and magnetic moment canting angles can persist even in the presence of large noncubic local distortions. Our results explain the origin of the forbidden Bragg peaks recently observed in neutron diffraction experiments and reconcile the observations of strong tetragonal distortion and perfect magnetoelastic locking in Sr_2IrO_4.

Item Type:

Article

Related URLs:

URL	URL Type	Description
https://doi.org/10.1103/PhysRevLett.114.096404	DOI	Article
https://arxiv.org/abs/1411.0783	arXiv	Discussion Paper

ORCID:

Author	ORCID
Chu, H.	0000-0002-1989-9517
Hsieh, D.	0000-0002-0812-955X

Alternate Title:

A structural distortion induced magneto-elastic locking in Sr2IrO4 revealed through nonlinear optical harmonic generation

Additional Information:

© 2015 American Physical Society. Received 10 July 2014; published 5 March 2015. We acknowledge useful discussions with Feng Ye, Bryan Chakoumakos, Stephen Lovesey, Dmitry Khalyavin, Peter Woelfle and Stephen Wilson. D. H. acknowledges support by the U.S. Army Research Office under Grant No. W911NF-13-1-0059. Instrumentation for the NHG-RA setup was partially supported by a U.S. Army Research Office DURIP Award under Grant No. W911NF-13-1-0293. D. H. acknowledges funding provided by the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center (PHY-1125565) with support of the Gordon and Betty Moore Foundation through Grant No. GBMF1250. N. P. and Y. S. acknowledge NSF support via Grants No. DMR-1255544 and No. DMR-1005932. G. C. acknowledges NSF support via Grant No. DMR-1265162.

Group:

Institute for Quantum Information and Matter

Funders:

Funding Agency	Grant Number
Army Research Office (ARO)	W911NF-13-1-0059
Army Research Office (ARO)	W911NF-13-1-0293
NSF	PHY-1125565
Gordon and Betty Moore Foundation	GBMF1250
NSF	DMR-1255544
NSF	DMR-1005932
NSF	DMR-1265162
Institute for Quantum Information and Matter (IQIM)	UNSPECIFIED

Issue or Number:

DOI:

10.1103/PhysRevLett.114.096404

Record Number:

CaltechAUTHORS:20141117-101456748

Persistent URL:

https://resolver.caltech.edu/CaltechAUTHORS:20141117-101456748

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No commercial reproduction, distribution, display or performance rights in this work are provided.

ID Code:

51833

Collection:

CaltechAUTHORS

Deposited By:

Ruth Sustaita

Deposited On:

17 Nov 2014 21:06

Last Modified:

10 Nov 2021 19:16

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