On the Stability of Quantum Hall Kagome-ice Insulator

The stability of the kagome-ice insulator against the three dimensionality and the canting angle of the spin anisotropy axes is studied numerically using the exact diagonalization method. The kagome-ice insulator, which was recently found at 2/3 electron filling in the double-exchange model on a kagome lattice, is a Chern insulator showing a quantized Hall response despite the absence of magnetic long-range order. We find that this peculiar state remains stable when the lattice is extended to three dimensions in an anisotropic pyrochlore lattice in the weak interlayer coupling region. On the other hand, we show that the kagome-ice insulator is also stable against the change of the canting angle. Furthermore, we find another kagome-ice insulator at 1/3 filling in a different range of the canting angle. Our results indicate that the quantum anomalous Hall response is widely observed in the variants of the kagome-ice double-exchange systems.