| Autor: |
Zhang, Xinshu, Mahmood, Fahad, Daum, Marcus, Dun, Zhiling, Paddison, Joseph A. M., Laurita, Nicholas J., Hong, Tao, Zhou, Haidong, Armitage, N. P., Mourigal, Martin |
| Rok vydání: |
2017 |
| Předmět: |
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| Zdroj: |
Phys. Rev. X 8, 031001 (2018) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1103/PhysRevX.8.031001 |
| Popis: |
The spin-1/2 triangular lattice antiferromagnet YbMgGaO$_{4}$ has attracted recent attention as a quantum spin-liquid candidate with the possible presence of off-diagonal anisotropic exchange interactions induced by spin-orbit coupling. Whether a quantum spin-liquid is stabilized or not depends on the interplay of various exchange interactions with chemical disorder that is inherent to the layered structure of the compound. We combine time-domain terahertz spectroscopy and inelastic neutron scattering measurements in the field polarized state of YbMgGaO$_{4}$ to obtain better microscopic insights on its exchange interactions. Terahertz spectroscopy in this fashion functions as high-field electron spin resonance and probes the spin-wave excitations at the Brillouin zone center, ideally complementing neutron scattering. A global spin-wave fit to all our spectroscopic data at fields over 4T, informed by the analysis of the terahertz spectroscopy linewidths, yields stringent constraints on $g$-factors and exchange interactions. Our results paint YbMgGaO$_{4}$ as an easy-plane XXZ antiferromagnet with the combined and necessary presence of sub-leading next-nearest neighbor and weak anisotropic off-diagonal nearest-neighbor interactions. Moreover, the obtained $g$-factors are substantially different from previous reports. This works establishes the hierarchy of exchange interactions in YbMgGaO$_{4}$ from high-field data alone and thus strongly constrains possible mechanisms responsible for the observed spin-liquid phenomenology. |
| Databáze: |
arXiv |
| Externí odkaz: |
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