Abstract
The phase diagram of a spin-1/2 model is investigated by means of exact diagonalizations on finite samples. This model is a generalization of the model on the square lattice with two different nearest-neighbor couplings and may also be viewed as an array of coupled Heisenberg chains. The results suggest that the resonating valence bond state predicted by Nersesyan and Tsvelik [Phys. Rev. B 67, 024422 (2003)] for is realized and extends beyond the limit of small interchain coupling along a curve nearly coincident with the line where the energy per spin is maximum. This line is likely bordered on both sides by a columnar dimer long range order. This columnar order could extend for which correspond to the model.
- Received 3 July 2003
DOI:https://doi.org/10.1103/PhysRevB.69.094418
©2004 American Physical Society