From quantum anomalous Hall phases to topological metals in interacting decorated honeycomb lattices

Abstract: An analysis of the stability of topological states induced by Coulomb repulsion on decorated honeycomb lattices is presented. Based on a mean-field treatment of a spinless extended Hubbard model on the decorated honeycomb lattice we show how the quantum anomalous Hall (QAH) phase is a robust topological phase which emerges at various electron fillings and involves either quadratic band crossing points (QBCP) or Dirac points of the bands. The topological QAH phase is also found to be most stable against thermal fluctuations up to moderate temperatures when the Coulomb repulsion is maximally frustrated. We show how a topological metal can be induced from the QAH by electron doping the system in a broad electron doping range. Electrons on the Fermi surface of such metallic states are characterized by having a non-zero Berry phase which gives rise to a non-zero intrinsic quantum Hall conductivity.