We study the electronic instabilities of the Hubbard model in the 1/6 hole-doped Kagome lattice using the variational cluster approach. The 1/6 hole doping is unique in the sense that the Fermi level is at the von Hove singularity and the Fermi surface has a perfect nesting. In this case, a density wave is usually realized. However, we demonstrate here that the chiral dx2−y2+idxy superconducting state is most favorable when a small Hubbard interaction U(U<3.0t) is introduced, and a scalar chiral spin order is realized at large U(U>5.0t). Between them, a spin-disordered insulating state is proposed.
@article{arxiv.1110.6613,
title = {Correlation-driven chiral superconductivity and chiral spin order in doped kagome lattice},
author = {Shun-Li Yu and Jian-Xin Li},
journal= {arXiv preprint arXiv:1110.6613},
year = {2012}
}