Chern Half Metals: A New Class of Topological Materials to Realize the Quantum Anomalous Hall Effect

The search of new topological insulators that demonstrate the quantum anomalous Hall effect (QAHE) is a cutting-edge research topic in condensed matter physics and materials science. So far, the QAHE has been observed only in Cr-doped (Bi,Sb)2Te3 at extremely low temperature. Therefore, it is important to find new materials with large topological band gap and high thermal stability for the realization of the QAHE. Based on first-principles and tight-binding model calculations, we discovered a new class of topological phase$-$Chern half metal which manifests the QAHE in one spin channel while is metallic in the other spin channel$-$in Co or Rh deposited graphene. Meanwhile, these systems have large perpendicular magnetic anisotropy energies of 5.3 and 11.5 meV, necessary for the observation of the QAHE at reasonably high temperature.