Conetronics in 2D metal-organic frameworks: double/half Dirac cones and quantum anomalous Hall effect

Bandstructure with Dirac cones gives rise to massless Dirac fermions with rich physics, and here we predict rich cone properties in M ₃C₁₂S₁₂ and M ₃C₁₂O₁₂, where M  = Zn, Cd, Hg, Be, or Mg based on recently synthesized Ni₃C₁₂S₁₂—class 2D metal-organic frameworks (MOFs). For M ₃C₁₂S₁₂, their band structures exhibit double Dirac cones with different Fermi velocities that are n (electron) and p (hole) type, respectively, which are switchable by few-percent strain. The crossing of two cones are symmetry-protected to be non-hybridizing, leading to two independent channels at the same k-point akin to spin-channels in spintronics, rendering 'conetronics' device possible. For M ₃C₁₂O₁₂, together with conjugated metal-tricatecholate polymers M ₃(HHTP)₂, the spin-polarized slow Dirac cone center is pinned precisely at the Fermi level, making the systems conducting in only one spin/cone channel. Quantum anomalous Hall effect can arise in MOFs with non-negligible spin–orbit coupling like Cu₃C₁₂O₁₂. Compounds of M ₃C₁₂S₁₂ and M ₃C₁₂O₁₂ with different M , can be used to build spin/cone-selecting heterostructure devices tunable by strain or electrostatic gating, suggesting their potential applications in spintroincs/conetronics. (paper)