Antiferromagnetic Spin Ladders with Odd and Even number of Chains
Abstract
We construct frustrated antiferromagnetic spin ladders with m chains for which the exact ground state can be determined in a particular parameter regime. The excitation spectrum is shown rigorously to be gapless ( with gap ) for odd ( even ) m. In a general parameter regime, the four-chain and periodic ladders are studied using a mean-field theory based on the bond operator formalism for spin . The excitation spectrum and the spin-gap are calculated in both the cases. The spin-gap of the frustrated ladder system has a larger magnitude than in the case of non-frustrated ladders. For the frustrated periodic ladder, the spin-gap vanishes at a critical value of the interladder coupling strength which is larger than the critical value in the case of non-frustrated periodic ladder.
Keywords
Cite
@article{arxiv.cond-mat/9610213,
title = {Antiferromagnetic Spin Ladders with Odd and Even number of Chains},
author = {Asimkumar Ghosh and Indrani Bose},
journal= {arXiv preprint arXiv:cond-mat/9610213},
year = {2009}
}
Comments
22 pages, LaTeX, 6 figures available upon request, submitted to Phys. Rev. B