Magnetic Real Chern Insulator in 2D Metal-Organic Frameworks

Xiaoming Zhang; Tingli He; Ying Liu; Xuefang Dai; Guodong Liu; Cong Chen; Weikang Wu; Jiaojiao Zhu; Shengyuan A Yang

doi:10.1021/acs.nanolett.3c01723

Magnetic Real Chern Insulator in 2D Metal-Organic Frameworks

Nano Lett. 2023 Aug 23;23(16):7358-7363. doi: 10.1021/acs.nanolett.3c01723. Epub 2023 Aug 3.

Authors

Xiaoming Zhang^{1

2}, Tingli He^{1

2}, Ying Liu^{1

2}, Xuefang Dai^{1

2}, Guodong Liu^{1

2}, Cong Chen^{3

4}, Weikang Wu⁵, Jiaojiao Zhu⁶, Shengyuan A Yang⁶

Affiliations

¹ State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China.
² School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, China.
³ Department of Physics, The University of Hong Kong, Hong Kong, China.
⁴ HKU-UCAS Joint Institute of Theoretical and Computational Physics at Hong Kong, Hong Kong, China.
⁵ Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China.
⁶ Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore.

PMID: 37535707
DOI: 10.1021/acs.nanolett.3c01723

Abstract

Real Chern insulators have attracted great interest, but so far, their material realization is limited to nonmagnetic crystals and systems without spin-orbit coupling. Here, we reveal the magnetic real Chern insulator (MRCI) state in a recently synthesized metal-organic framework material Co₃(HITP)₂. Its ground state with in-plane ferromagnetic ordering hosts a nontrivial real Chern number, enabled by the C_2zT symmetry and robustness against spin-orbit coupling. Distinct from previous nonmagnetic examples, the topological corner zero modes of MRCIs are spin-polarized. Furthermore, under small tensile strains, the material undergoes a topological phase transition from the MRCI to a magnetic double-Weyl semimetal phase, via a pseudospin-1 critical state. Similar physics can also be found in closely related materials Mn₃(HITP)₂ and Fe₃(HITP)₂, which also exist. Possible experimental detections and implications of an emerging magnetic flat band in the system are discussed.

Keywords: corner states; flat band; real Chen insulator; spin polarization.