English

Quantum phase diagram of an exactly solved mixed spin ladder

Statistical Mechanics 2009-11-10 v1

Abstract

We investigate the quantum phase diagram of the exactly solved mixed spin-(1/2,1) ladder via the thermodynamic Bethe ansatz (TBA). In the absence of a magnetic field the model exhibits three quantum phases associated with su(2), su(4) and su(6) symmetries. In the presence of a strong magnetic field, there is a third and full saturation magnetization plateaux within the strong antiferromagnetic rung coupling regime. Gapless and gapped phases appear in turn as the magnetic field increases. For weak rung coupling, the fractional magnetization plateau vanishs and exhibits new quantum phase transitions. However, in the ferromagnetic coupling regime, the system does not have a third saturation magnetization plat eau. The critical behaviour in the vicinity of the critical points is also derived systematically using the TBA.

Keywords

Cite

@article{arxiv.cond-mat/0309267,
  title  = {Quantum phase diagram of an exactly solved mixed spin ladder},
  author = {M. T. Batchelor and X. -W. Guan and N. Oelkers and Z. -J. Ying},
  journal= {arXiv preprint arXiv:cond-mat/0309267},
  year   = {2009}
}

Comments

20 pages, 2 figures