Collective Modes of a Helical Liquid
Collective Modes of a Helical Liquid
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DOI：
10.1103/physrevlett.104.116401
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发表时间：
2010-03-19
影响因子：
8.6
通讯作者：
Zhang, Shou-Cheng
中科院分区：
文献类型：
--
作者：
Raghu, S.;Chung, Suk Bum;Zhang, Shou-Cheng
研究了拓扑绝缘体表面螺旋金属的低能集体模和输运性质。在低能量下，表面的电输运和自旋动力学通过将电流等同于自旋自由度的面内分量的算子恒等式精确地相关。从这个关系可以看出，无阻尼的自旋波总是伴随着螺旋金属中的声音模式，因此有可能“听到”自旋的声音。在存在长程库仑相互作用的情况下，表面等离子体激元模式也耦合到自旋波，产生杂化的“自旋-等离子体激元”模式。我们对Bi（2）Se（3）中的自旋等离子体激元作了定量预测，并讨论了它在自旋光栅实验中的探测。
We study low energy collective modes and transport properties of the "helical metal" on the surface of a topological insulator. At low energies, electrical transport and spin dynamics at the surface are exactly related by an operator identity equating the electric current to the in-plane components of the spin degrees of freedom. From this relation it follows that an undamped spin wave always accompanies the sound mode in the helical metal-thus it is possible to "hear" the sound of spins. In the presence of long range Coulomb interactions, the surface plasmon mode is also coupled to the spin wave, giving rise to a hybridized "spin-plasmon" mode. We make quantitative predictions for the spin-plasmon in Bi(2)Se(3), and discuss its detection in a spin-grating experiment.