Chiral Spin Mode on the Surface of a Topological Insulator
| Autor: | Kung, H. -H., Maiti, S., Wang, X., Cheong, S. -W., Maslov, D. L., Blumberg, G. |
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| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | Phys. Rev. Lett. 119, 136802 (2017) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevLett.119.136802 |
| Popis: | Using polarization-resolved resonant Raman spectroscopy, we explore collective spin excitations of the chiral surface states in a three dimensional topological insulator, Bi$_2$Se$_3$. 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. Comment: 9 pages, 7 figures, accepted for publication in Phys. Rev. Lett |
| Databáze: | arXiv |
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