  Quantum anomalous Hall effect (QAHE) is a fundamental transport phenomenon in
the field of condensed-matter physics. Without external magnetic field,
spontaneous magnetization combined with spin-orbit coupling give rise to a
quantized Hall conductivity. So far, a number of theoretical proposals have
been made to realize the QAHE, but all based on inorganic materials. Here,
using first-principles calculations, we predict a family of 2D organic
topological insulators (OTIs) for realizing the QAHE. Designed by assembling
molecular building blocks of triphenyl-transition-metal compounds into a
hexagonal lattice, this new classes of organic materials are shown to have a
nonzero Chern number and exhibit a gapless chiral edge state within the Dirac
gap.
