Spin-layer locking induced second-order nonlinear effect in centrosymmetric crystals

Yanchong Zhao, Luojun Du, Jing Liang, Mohammad Bahramy, Mingwei Yang, Yao Guang, Zheng Wei, Mengzhou Liao, Jian Tang, Jiaojiao Zhao, Cheng Shen, Xiaomei Li, Qinqin Wang, Rong Yang, Dongxia Shi, Kaihui Liu, Zhipei Sun, Guangyu Zhang

Research output: Other contributionpeer-review

Abstract

According to the generally accepted nonlinear principles, second-order nonlinear effect (SONE) is strongly inhibited by the crystalline symmetries and thus can manifest only in non-centrosymmetric materials with broken global spatial inversion symmetry. In stark contrast, here we report the observation of direct-current (DC) related SONE, including circular and linear photogalvanic effects, in centrosymmetric bilayer and multilayer MoS2. In conjunction with relativistic first-principles calculations, we uncover that the observed DC-related SONE in inversion-symmetric MoS2 results from the localized electronic states and the locking of spin with the layer and valley pseudospins. Our results provide a new insight into nonlinear physics and would be applicable to other phenomena thus far believed to occur only in non-centrosymmetric systems, such as quantum spin Hall effect, valley Hall effect, piezoelectricity and unconventional Ising superconductivity.
Original languageEnglish
Number of pages19
DOIs
Publication statusPublished - 29 Dec 2020

Keywords

  • nonlinear principles
  • second-order nonlinear effect 29 (SONE)

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