Observation of terahertz magnon of Kaplan-Kittel exchange resonance in yttrium-iron garnet by Raman spectroscopy
Observation of terahertz magnon of Kaplan-Kittel exchange resonance in yttrium-iron garnet by Raman spectroscopy
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DOI：
10.1103/physrevb.102.174432
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发表时间：
2020-05
影响因子：
3.7
通讯作者：
W. Hsu;K. Shen;Y. Fujii;A. Koreeda;T. Satoh
中科院分区：
文献类型：
--
作者：
W. Hsu;K. Shen;Y. Fujii;A. Koreeda;T. Satoh
利用线偏振光和圆偏振光对钇铁石榴石单晶进行了背散射拉曼光谱研究。发现了一个Kaplan-Kittel（KK）交换共振的THz磁振子，它被认为是光学方法无法观察到的。在80 K时，KK交换共振频率为7.8 THz，偏振选择规则导致$A {2}$模的反对称拉曼张量。此外，还完成了3$A_{\rm 1g}$，8$E_{\rm g}$和14$T_{\rm 2g}$拉曼激活声子模的归属。本研究将促进对太赫兹磁振子与声子耦合的进一步研究，为太赫兹光磁学的发展铺平道路。
Backscattering Raman spectroscopic investigations were performed on an yttrium-iron garnet single crystal using linearly and circularly polarized light. A THz magnon of the Kaplan-Kittel (KK) exchange resonance was discovered, which had been regarded as unobservable by optical methods. The KK exchange resonance had 7.8 THz frequency at 80 K, and the polarization selection rule led to an antisymmetric Raman tensor of $A_{2}$ mode. Besides, assignment of all the Raman-active phonon modes, 3$A_{\rm 1g}$, 8$E_{\rm g}$, and 14$T_{\rm 2g}$, was completed. This study will stimulate further investigation on the coupling of THz magnons and phonons and pave the way toward THz opto-magnonics.