Author(s): Yu, JL (Yu, Jinling); Wu, WY (Wu, Wenyi); Wang, YM (Wang, Yumeng); Zhu, KJ (Zhu, Kejing); Zeng, XL (Zeng, Xiaolin); Chen, YH (Chen, Yonghai); Liu, Y (Liu, Yu); Yin, CM (Yin, Chunming); Cheng, SY (Cheng, Shuying); Lai, YF (Lai, Yunfeng); He, K (He, Ke); Xue, QK (Xue, Qikun)
Source: APPLIED PHYSICS LETTERS Volume: 116 Issue: 14 DOI: 10.1063/1.5145359 Published: APR 6 2020
Abstract: Topological insulators (TIs) are considered as ideal spintronic materials due to the spin-momentum-locked Dirac surface states. The photoinduced anomalous Hall effect (PAHE) is a powerful tool to investigate the spin Hall effect of topological insulators even at room temperature. In this Letter, the PAHE has been observed in three dimensional topological insulator Bi2Te3 thin films grown on Si substrates at room temperature. As the thickness of the Bi2Te3 films increases from 3 to 20 quintuple layer (QL), the PAHE first increases and then decreases, and it reaches a maximum at 7 QL. The sign reversal of the PAHE of the 3 QL sample after oxidation reveals that the PAHE of the Bi2Te3 thin films is dominated by the top surface states, which is further confirmed by the circular photogalvanic effect under front and back illuminations. The photoinduced anomalous Hall conductivity excited by 1064nm light is as large as 5.28nA V-1 W-1 cm(2) in the 7 QL sample, much larger than that observed in InGaAs/AlGaAs quantum wells (0.445nA V-1 W-1 cm(2)) and GaN/AlGaN heterostructures (0.143nA V-1 W-1 cm(2)). By comparing the PAHE current excited by 1064nm with that excited by 1342nm, we reveal that the tremendous PAHE excited by 1064nm light is due to the modulation effect of spin injection from Si substrates. The giant PAHE value observed in TI Bi2Te3 may offer spintronic applications of TIs such as high-efficient light-polarization-state detectors.
Accession Number: WOS:000526892600004
ISSN: 0003-6951
eISSN: 1077-3118
Full Text: https://aip.scitation.org/doi/10.1063/1.5145359