Instabilities of interacting electrons on the triangular lattice
Abstract
Motivated by the recent finding of superconductivity in layered CoO_2 compounds, we investigate superconducting and magnetic instabilities of interacting electrons on the two-dimensional triangular lattice. Using a one-loop renormalization group scheme for weak to moderate coupling strengths, we find that for purely local interactions U>0 and small Fermi surfaces the renormalization group flow remains bounded down to very low scales and no superconducting or other instabilities can be detected. Antiferromagnetic exchange interactions J generate a wide density region with a d_{x^2-y^2}+id_{xy}-wave superconducting instability similar to recent proposals for the strongly correlated t-J model. For larger Fermi surface volumes the interactions flow to strong coupling also for purely local interactions U>0. We find a singlet pairing instability in the vicinity of strong magnetic ordering tendencies at three wavevectors for the van Hove filling.
Cite
@article{arxiv.cond-mat/0304460,
title = {Instabilities of interacting electrons on the triangular lattice},
author = {Carsten Honerkamp},
journal= {arXiv preprint arXiv:cond-mat/0304460},
year = {2009}
}
Comments
10 pages, 7 figures, submitted to Phys. Rev. B