  Quantum anomalous Hall (QAH) insulator is a topological phase which exhibits
chiral edge states in the absence of magnetic field. The celebrated Haldane
model is the first example of QAH effect, but difficult to realize. Here, we
predict the two-dimensional single-atomic-layer V2O3 with a honeycomb-Kagome
structure is a QAH insulator with a large band gap (large than 0.1 eV) and a
high ferromagnetic Curie temperature (about 900 K). Combining the
first-principle calculations with the effective Hamiltonian analysis, we find
that the spin-majority dxy and dyz orbitals of V atoms on the honeycomb lattice
form a massless Dirac cone near the Fermi level which becomes massive when the
on-site spin-orbit coupling is included. Interestingly, we find that the large
band gap is caused by a cooperative effect of electron correlation and
spin-orbit coupling. Both first-principle calculations and the effective
Hamiltonian analysis confirm that 2D V2O3 has a non-zero Chern number (i.e.,
one). Our work paves a new direction towards realizing the QAH effect at room
temperature.
