中国物理B ›› 2023, Vol. 32 ›› Issue (9): 97101-097101.doi: 10.1088/1674-1056/acd920

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Design of sign-reversible Berry phase effect in 2D magneto-valley material

Yue-Tong Han(韩曰通), Yu-Xian Yang(杨宇贤), Ping Li(李萍), and Chang-Wen Zhang(张昌文)   

  1. School of Physics and Technology, University of Jinan, Jinan 250022, China
  • 收稿日期:2022-12-06 修回日期:2023-05-09 接受日期:2023-05-26 发布日期:2023-09-01
  • 通讯作者: Chang-Wen Zhang E-mail:ss_zhangchw@ujn.edu.cn
  • 基金资助:
    Project supported by the Taishan Scholar Program of Shandong Province, China (Grant No. ts20190939), the Independent Cultivation Program of Innovation Team of Jinan City (Grant No. 2021GXRC043), and the National Natural Science Founation of China (Grant No. 52173283).

Design of sign-reversible Berry phase effect in 2D magneto-valley material

Yue-Tong Han(韩曰通), Yu-Xian Yang(杨宇贤), Ping Li(李萍), and Chang-Wen Zhang(张昌文)   

  1. School of Physics and Technology, University of Jinan, Jinan 250022, China
  • Received:2022-12-06 Revised:2023-05-09 Accepted:2023-05-26 Published:2023-09-01
  • Contact: Chang-Wen Zhang E-mail:ss_zhangchw@ujn.edu.cn
  • Supported by:
    Project supported by the Taishan Scholar Program of Shandong Province, China (Grant No. ts20190939), the Independent Cultivation Program of Innovation Team of Jinan City (Grant No. 2021GXRC043), and the National Natural Science Founation of China (Grant No. 52173283).

摘要: Manipulating sign-reversible Berry phase effects is both fundamentally intriguing and practically appealing for searching for exotic topological quantum states. However, the realization of multiple Berry phases in the magneto-valley lattice is rather challenging due to the complex interactions from spin-orbit coupling (SOC), band topology, and magnetic ordering. Here, taking single-layer spin-valley RuCl2 as an example, we find that sign-reversible Berry phase transitions from ferrovalley (FV) to half-valley semimetal (HVS) to quantum anomalous valley Hall effect (QAVHE) can be achieved via tuning electronic correlation effect or biaxial strains. Remarkably, QAVHE phase, which combines both the features of quantum anomalous Hall and anomalous Hall valley effect, is introduced by sign-reversible Berry curvature or band inversion of dxy/dx2-y2 and dz2 orbitals at only one of the K/K' valleys of single-layer RuCl2. And the boundary of QAVHE phase is the HVS state, which can achieve 100% intrinsically valley polarization. Further, a k·p model unveiled the valley-controllable sign-reversible Berry phase effects. These discoveries establish RuCl2 as a promising candidate to explore exotic quantum states at the confluence of nontrivial topology, electronic correlation, and valley degree of freedom.

关键词: valley polarization, topological phase transition, half-valley semimetal, quantum anomalous valley Hall effect, first-principles calculations

Abstract: Manipulating sign-reversible Berry phase effects is both fundamentally intriguing and practically appealing for searching for exotic topological quantum states. However, the realization of multiple Berry phases in the magneto-valley lattice is rather challenging due to the complex interactions from spin-orbit coupling (SOC), band topology, and magnetic ordering. Here, taking single-layer spin-valley RuCl2 as an example, we find that sign-reversible Berry phase transitions from ferrovalley (FV) to half-valley semimetal (HVS) to quantum anomalous valley Hall effect (QAVHE) can be achieved via tuning electronic correlation effect or biaxial strains. Remarkably, QAVHE phase, which combines both the features of quantum anomalous Hall and anomalous Hall valley effect, is introduced by sign-reversible Berry curvature or band inversion of dxy/dx2-y2 and dz2 orbitals at only one of the K/K' valleys of single-layer RuCl2. And the boundary of QAVHE phase is the HVS state, which can achieve 100% intrinsically valley polarization. Further, a k·p model unveiled the valley-controllable sign-reversible Berry phase effects. These discoveries establish RuCl2 as a promising candidate to explore exotic quantum states at the confluence of nontrivial topology, electronic correlation, and valley degree of freedom.

Key words: valley polarization, topological phase transition, half-valley semimetal, quantum anomalous valley Hall effect, first-principles calculations

中图分类号:  (Density functional theory, local density approximation, gradient and other corrections)

  • 71.15.Mb
71.15.Dx (Computational methodology (Brillouin zone sampling, iterative diagonalization, pseudopotential construction)) 73.43.-f (Quantum Hall effects) 73.63.-b (Electronic transport in nanoscale materials and structures)