Chern insulators and high Curie temperature Dirac half-metal in two-dimensional metal-organic frameworks

Two-dimensional (2D) magnetic materials with nontrivial topological states have recently drawn considerable attention. Among them, 2D metal-organic frameworks (MOFs) are standing out due to their advantages such as the easy synthesis in practice and less sensitivity to oxidation that are distinctly different from inorganic materials. By means of density-functional theory calculations, we systematically investigate the electronic and topological properties of a class of 2D MOFs X(C21H15N3) (X = transition metal element from 3d to 5d). Excitingly, we find that X(C21H15N3) (X = Ti, Zr, Ag, Au) are Chern insulators with sizable band gaps (& SIM;7.1 meV). By studying a four-band effective model, it is revealed that the Chern insulator phase in X(C21H15N3) (X = Ti, Zr, Ag, Au) is caused cooperatively by the band inversion of the p orbitals of the C21H15N3 molecule and the intrinsic ferromagnetism of X(C21H15N3). Additionally, Mn(C21H15N3) is a Dirac half-metal ferromagnet with a high Curie temperature up to 156 K. Our work demonstrates that 2D MOFs X(C21H15N3) are good platforms for realizing the quantum anomalous Hall effect and designing spintronic devices based on half-metals with high-speed and long-distance spin transport.

Automated summary

This study systematically investigates the electronic and topological properties of a class of 2D metal-organic frameworks (MOFs). The results show that these MOFs exhibit desirable properties such as Chern insulation and high Curie temperature, making them promising for applications in quantum anomalous Hall effect and spintronic devices.