Realizing Topological Mott Insulators from the RKKY Interaction
Abstract
We engineer topological insulating phases in a fermion-fermion mixture on the honeycomb lattice, without resorting to artificial gauge fields or spin-orbit couplings and considering only local interactions. Essentially, upon integrating out the fast component (characterized by a larger hopping amplitude) in a finite region of dopings, we obtain an effective interaction between the slow fermions at half-filling, which acquires a Haldane mass with opposite parity in the two valleys of the Dirac cones, thus triggering a quantum anomalous Hall effect. We carefully analyze the competition between the induced Semenoff-type mass (producing charge density wave orders in real space) versus the Haldane mass (quantum anomalous Hall phase), as a function of the chemical potential of the fast fermions. If the second species involves spin-1/2 particles, this interaction may induce a quantum spin Hall phase. Such fermion-fermion mixtures can be realized in optical lattices or in graphene heterostructures.
Cite
@article{arxiv.1409.6237,
title = {Realizing Topological Mott Insulators from the RKKY Interaction},
author = {Tianhan Liu and Benoît Douçot and Karyn Le Hur},
journal= {arXiv preprint arXiv:1409.6237},
year = {2016}
}