Coexistence of topological and bipolar magnetic semiconducting behavior in 2D metal-organic frameworks with a p-orbital coloring-triangle lattice

Abstract

The recent emergence of two-dimensional metal-organic framework (MOF) materials with nontrivial magnetic and electronic properties has attracted great interest in spintronics. Here, we theoretically demonstrate the synthesis of a coloring-triangle latticed 2D MOF by assembling 2,3,6,7,10,11-hexahydroxytriphenylene (H6HOTP) species and threefold coordinated Mn atoms, namely, 2D Mn-HOTP. The electronic structure calculations shown that 2D Mn-HOTP exhibits coexistence of bipolar magnetic semiconducting and topological behavior. 2D Mn-HOTP is an intrinsic bipolar magnetic semiconductor with a small spin-flip band gap of 0.21 eV and relatively large spin-conserving band gaps of 0.34 and 0.74 eV. Electrical/hole doping can induce the transformation of 2D Mn-HOTP into half-metal conduction with controllable spin polarization direction. In addition, the organic HOTP ligands containing coloring-triangle lattice enable the formation of p-orbital single polarized Dirac cones and flat bands, which exhibit the topological properties such as nonzero Chern number and nontrivial edge states near the Fermi level. The Dirac points and flat bands can be selectively detected at the Fermi level with experimentally achievable electron and hole concentrations of 5.19 and 0.91 × 1013 cm−2, respectively. These results not only highlight that 2D Mn-HOTP MOF is a promising candidate for developing spintronic devices but also provide an ideal platform to explore kagome-like correlated quantum states.