The spin-1/2 square-lattice J_1-J_2 model: The spin-gap issue
Strongly Correlated Electrons
2015-01-16 v2
Abstract
We use the coupled cluster method to high orders of approximation in order to calculate the ground-state energy, the ground-state magnetic order parameter, and the spin gap of the spin-1/2 J_1-J_2 model on the square lattice. We obtain values for the transition points to the magnetically disordered quantum paramagnetic phase of J_2^{c1}=0.454J_1 and J_2^{c2}= 0.588 J_1. The spin gap is zero in the entire parameter region accessible by our approach, i.e. for J_2 \le 0.49J_1 and J_2 > 0.58J_1. This finding is in favor of a gapless spin-liquid ground state in this parameter regime.
Cite
@article{arxiv.1409.0193,
title = {The spin-1/2 square-lattice J_1-J_2 model: The spin-gap issue},
author = {J. Richter and R. Zinke and D. J. J. Farnell},
journal= {arXiv preprint arXiv:1409.0193},
year = {2015}
}
Comments
10 pages, 3 figures, accepted version