Quantum Anomalous Hall Effect and Conetronics

Based on recently synthesized Ni₃C₁₂S₁₂–class 2D metal-organic frameworks (MOFs), we predict electronic properties of M₃C₁₂S₁₂ and M₃C₁₂O₁₂, where M=Zn, Cd, Hg, Be, or Mg with no M orbital contributions to bands near Fermi level. For M₃C₁₂S₁₂, 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 in 2D node-line semimetals at the same k-point akin to spin-channels in spintronics, rendering “conetronics” device possible. Quantum anomalous Hall effect can arise in MOFs with non-negligible spin-orbit coupling like Cu3C12O12. We also propose that LaCl and LaBr monolayer and bulk forms, which were fabricated decades ago, can both exhibit intrinsic quantum anomalous Hall effect with an energy gap up to 36meV. These simple binary compounds are revealed to be ferromagnets and their estimated Curie temperature is higher than 400K. Along with the energy gap, the large Curie temperature guarantees that the quantum anomalous Hall effect survives at room-temperature.