中国物理B ›› 2025, Vol. 34 ›› Issue (2): 27304-027304.doi: 10.1088/1674-1056/ad9ffa

所属专题: SPECIAL TOPIC — Moiré physics in two-dimensional materials

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Correlated physics, charge and magnetic orders in moiré kagomé systems

Zhaochen Liu(刘兆晨)1,2 and Jing Wang(王靖)1,2,3,4,†   

  1. 1 State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China;
    2 Shanghai Research Center for Quantum Sciences, Shanghai 201315, China;
    3 Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China;
    4 Hefei National Laboratory, Hefei 230088, China
  • 收稿日期:2024-10-21 修回日期:2024-11-29 接受日期:2024-12-17 出版日期:2025-02-15 发布日期:2025-01-15
  • 通讯作者: Jing Wang E-mail:wjingphys@fudan.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12350404 and 12174066), the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0302600), the National Key Research and Development Program of China (Grant No. 2019YFA0308404), and the Science and Technology Commission of Shanghai Municipality (Grant Nos. 23JC1400600 and 2019SHZDZX01).

Correlated physics, charge and magnetic orders in moiré kagomé systems

Zhaochen Liu(刘兆晨)1,2 and Jing Wang(王靖)1,2,3,4,†   

  1. 1 State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China;
    2 Shanghai Research Center for Quantum Sciences, Shanghai 201315, China;
    3 Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China;
    4 Hefei National Laboratory, Hefei 230088, China
  • Received:2024-10-21 Revised:2024-11-29 Accepted:2024-12-17 Online:2025-02-15 Published:2025-01-15
  • Contact: Jing Wang E-mail:wjingphys@fudan.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12350404 and 12174066), the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0302600), the National Key Research and Development Program of China (Grant No. 2019YFA0308404), and the Science and Technology Commission of Shanghai Municipality (Grant Nos. 23JC1400600 and 2019SHZDZX01).

摘要: Moiré systems have emerged as an ideal platform for exploring interaction effects and correlated states. However, most of the experimental systems are based on either triangular or honeycomb lattices. In this study, based on the self-consistent Hartree-Fock calculation, we investigate the phase diagram of the kagomé lattice in a recently discovered system with two degenerate $\varGamma$ valley orbitals and strong spin-orbit coupling. By focusing on the filling factors of $1/2$, $1/3$ and $2/3$, we identify various symmetry-breaking states by adjusting the screening length and dielectric constant. At the half filling, we discover that the spin-orbit coupling induces Dzyaloshinskii-Moriya interaction and stabilizes a classical magnetic state with $120^\circ$ ordering. Additionally, we observe a transition to a ferromagnetic state with out-of-plane ordering. In the case of $1/3$ filling, the system is ferromagnetically ordered due to the lattice frustration. Furthermore, for $2/3$ filling, the system exhibits a pinned droplet state and a $120^\circ$ magnetic ordered state at weak and immediate coupling strengths, respectively. For the strong coupling case, when dealing with non-integer filling, the system is always charge ordered with sublattice polarization. Our study serves as a starting point for exploring the effects of correlation in moiré kagomé systems.

关键词: moiré kagomé system, Hartree-Fock, spin-orbit coupling

Abstract: Moiré systems have emerged as an ideal platform for exploring interaction effects and correlated states. However, most of the experimental systems are based on either triangular or honeycomb lattices. In this study, based on the self-consistent Hartree-Fock calculation, we investigate the phase diagram of the kagomé lattice in a recently discovered system with two degenerate $\varGamma$ valley orbitals and strong spin-orbit coupling. By focusing on the filling factors of $1/2$, $1/3$ and $2/3$, we identify various symmetry-breaking states by adjusting the screening length and dielectric constant. At the half filling, we discover that the spin-orbit coupling induces Dzyaloshinskii-Moriya interaction and stabilizes a classical magnetic state with $120^\circ$ ordering. Additionally, we observe a transition to a ferromagnetic state with out-of-plane ordering. In the case of $1/3$ filling, the system is ferromagnetically ordered due to the lattice frustration. Furthermore, for $2/3$ filling, the system exhibits a pinned droplet state and a $120^\circ$ magnetic ordered state at weak and immediate coupling strengths, respectively. For the strong coupling case, when dealing with non-integer filling, the system is always charge ordered with sublattice polarization. Our study serves as a starting point for exploring the effects of correlation in moiré kagomé systems.

Key words: moiré kagomé system, Hartree-Fock, spin-orbit coupling

中图分类号:  (Electron states at surfaces and interfaces)

  • 73.20.-r
73.43.Cd (Theory and modeling) 71.70.Ej (Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect) 68.65.-k (Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties)