Chiral Spin Mode on the Surface of a Topological Insulator
Chiral Spin Mode on the Surface of a Topological Insulator
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DOI：
10.1103/physrevlett.119.136802
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发表时间：
2017-09-27
影响因子：
8.6
通讯作者：
Blumberg, G.
中科院分区：
文献类型：
--
作者：
Kung, H-H.;Maiti, S.;Blumberg, G.
利用偏振分辨共振拉曼光谱，我们研究了三维拓扑绝缘体Bi2Se3中手征表面态的集体自旋激发.在拉曼谱的赝矢量A（2）对称通道中观察到一个150 meV的尖峰。通过与计算结果的比较，我们确定了这个峰是表面狄拉克费米子的横向集体自旋模。与狄拉克等离子体激元或表面等离子体激元不同，这种模式类似于部分极化费米液体中的自旋波，自旋轨道耦合起着有效磁场的作用。
Using polarization-resolved resonant Raman spectroscopy, we explore collective spin excitations of the chiral surface states in a three dimensional topological insulator, Bi2Se3. We observe a sharp peak at 150 meV in the pseudovector A(2) symmetry channel of the Raman spectra. By comparing the data with calculations, we identify this peak as the transverse collective spin mode of surface Dirac fermions. This mode, unlike a Dirac plasmon or a surface plasmon in the charge sector of excitations, is analogous to a spin wave in a partially polarized Fermi liquid, with spin-orbit coupling playing the role of an effective magnetic field.