Structural Distortion-Induced Magnetoelastic Locking inSr2IrO4Revealed through Nonlinear Optical Harmonic Generation
| Autor: | Y. Sizyuk, Hao Chu, David Hsieh, Gang Cao, T.F. Qi, Liuyan Zhao, Natalia B. Perkins, Darius H. Torchinsky |
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| Rok vydání: | 2015 |
| Předmět: |
Physics
Magnetic moment Condensed matter physics Neutron diffraction General Physics and Astronomy Condensed Matter::Materials Science symbols.namesake Tetragonal crystal system Superexchange symbols High harmonic generation Condensed Matter::Strongly Correlated Electrons Strongly correlated material Hamiltonian (quantum mechanics) Néel temperature |
| Zdroj: | Physical Review Letters. 114 |
| ISSN: | 1079-7114 0031-9007 |
| Popis: | 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 Neel 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. |
| Databáze: | OpenAIRE |
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