Alternating Heisenberg Spin-1/2 Chains in a Transverse Magnetic Field
The ground-state phase diagram of alternating spin-1/2 chains with anisotropic ferromagnetic coupling under the influence of a symmetry-breaking transverse magnetic field is studied using 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 hc1 and hc2, corresponding to the transition between different magnetic phases of the system. It is found that the intermediate state (hc1<h<hc2) is gapful, and describes the stripe-antiferromagnetic phase.
Journal of the Physical Society of Japan
- Pub Date:
- February 2008
- Condensed Matter - Strongly Correlated Electrons
- 6 pages, 7 figures