We consider the Kondo-lattice model on the kagome lattice and study its weak-coupling instabilities at band filling fractions for which the Fermi surface has singularities. These singularites include Dirac points, quadratic Fermi points in contact with a flat band, and Van Hove saddle points. By combining a controlled analytical approach with large-scale numerical simulations, we demonstrate that the weak-coupling instabilities of the Kondo-lattice model lead to exotic magnetic orderings. In particular, some of these magnetic orderings produce a spontaneous quantum anomalous Hall state.
@article{arxiv.1407.5369,
title = {Novel magnetic orderings in the kagome Kondo-lattice model},
author = {Kipton Barros and Jörn W. F. Venderbos and Gia-Wei Chern and C. D. Batista},
journal= {arXiv preprint arXiv:1407.5369},
year = {2014}
}