Spin-gap phase of a quantum spin system on a honeycomb lattice
Abstract
We study a quantum spin system on a honeycomb lattice, when it includes frustration and distortion in antiferromagnetic (AF) exchange interactions. We transform the spin system onto a nonlinear sigma model (NLSM) in a new way preserving the original spin degrees of freedom. Assisted by a renormalization- group argument, the NLSM provides a ground-state phase diagram consisting of an ordered AF phase and a disordered spin-gap phase. The spin-gap phase extends from a strong frustration regime to a strong distortion regime, showing that the disordered ground states are essentially the same in both the regimes. In the spin-half case, the spin-gap phase for the spin system on a honeycomb lattice is larger than that for the J1-J2 model on a square lattice.
Cite
@article{arxiv.cond-mat/0609446,
title = {Spin-gap phase of a quantum spin system on a honeycomb lattice},
author = {Ken'ichi Takano},
journal= {arXiv preprint arXiv:cond-mat/0609446},
year = {2009}
}
Comments
4 pages with 2 figures; accepted in Phys. Rev. B