期刊
PHYSICAL REVIEW LETTERS
卷 121, 期 2, 页码 -出版社
AMER PHYSICAL SOC
DOI: 10.1103/PhysRevLett.121.026807
关键词
-
资金
- National Science Foundation [EFMA-1641101]
Topological insulators are promising candidates for optically driven spintronic devices, because photoexcitation of spin polarized surface states is governed by angular momentum selection rules. We carry out femtosecond midinfrared spectroscopy on thin films of the topological insulator Bi2Te2Se, which has a higher surface state conductivity compared to conventionally studied Bi2Se3 and Bi2Te3. Both charge and spin dynamics are probed utilizing circularly polarized light. With a sub-band-gap excitation, clear helicity-dependent dynamics is observed only in thin (<20 nm) flakes. On the other hand, such dependence is observed for both thin and thick flakes with above-band-gap excitation. The helicity dependence is attributed to asymmetric excitation of the Dirac-like surface states. The observed long-lasting asymmetry over 10 ps even at room temperature indicates low backscattering of surface state carriers which can be exploited for spintronic devices.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据