Alternating Heisenberg Spin-1/2 Chains in a Transverse Magnetic Field
arXiv:0711.0623 · doi:10.1143/JPSJ.77.024710
Abstract
The ground state phase diagram of the alternating spin-1/2 chains with anisotropic ferromagnetic coupling under the influence of a symmetry breaking transverse magnetic field is studied. We have used the exact diagonalization technique. In the limit where the antiferromagnetic coupling is dominant, we have identified two Ising-type quantum phase transitions. We have calculated two critical fields and , corresponding to the transition between different magnetic phases of the system. It is found that the intermediate state () is gapful, describing the stripe-antiferromagnetic phase.
6 pages, 7 figures