Antiferromagnetic Spin Ladders with Odd and Even number of Chains
arXiv:cond-mat/9610213 · doi:10.1103/PhysRevB.55.3613
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.
22 pages, LaTeX, 6 figures available upon request, submitted to Phys. Rev. B
References in corpus (5)
- Surprises on the Way from 1D to 2D Quantum Magnets: the Novel Ladder Materials
- Equivalence of the antiferromagnetic Heisenberg ladder to a single chain
- Strong Coupling Expansions for Antiferromagnetic Heisenberg S=1/2 Ladders
- Density Matrix Renormalization Group Study of the Spin 1/2 Heisenberg Ladder with Antiferromagnetic Legs and Ferromagnetic Rungs
- Absence of gap for infinite half--integer spin ladders with an odd number of legs