Unusual Janus Bi 2 TeSe 2 Topological Insulators Displaying Second-Harmonic Generation, Linear-in-Temperature Resistivity, and Weak Antilocalization

• Published in: Journal of the American Chemical Society Vol. 146; no. 26; pp. 17784 - 17792
• Main Authors: Zou, Xiaobin, Yuan, Xuanhao, Liang, Lishan, Tian, Fei, Li, Yan, Sun, Yong, Wang, Chengxin
• Format: Journal Article
• Language: English
• Published: United States 03-07-2024
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.4c03176

Well-established knowledge about inversion-symmetric Bi
Te
Se
topological insulators characterizes the promising new-generation quantum device. Noticeably, the inversion asymmetric phase containing different surface electronic structures may create an extra topological phenomenon pointing to a new device paradigm. Herein, Janus Bi
TeSe
single-crystal nanosheets with an unconventional stacking sequence of Se-Bi-Se-Bi-Te are realized via chemical vapor deposition growth, which is clarified by atomically resolved AC-STEM and elemental mapping. An obvious polarization-dependent second-harmonic generation with a representative 6-fold rotational symmetry is detected due to the broken out-of-plane mirror symmetry in this system. Low-temperature transport measurements display a strange metal-like linear-in-temperature resistivity. Anomalous conductance peaks under low magnetic fields induced by the weak antilocalization effect of topological surface states and the two-dimensional transport-dominated anisotropic magnetoresistance are revealed. These findings correlate the Janus Bi
TeSe
phase with emerging physics topics, which would inspire fresh thoughts in well-developed Bi
Te
Se
topological insulators and open up opportunities for exploring hybrid nonlinear optoelectronic topological devices.