arXiv:cond-mat/0009481 · Physical review. B, Condensed matter
Magnetization plateaus and phase diagram in polymerized S=1/2 XXZ chains
Wei Chen, Kazuo Hida, B. C. Sanctuary
Abstract
The magnetization plateaus of polymerized $S=\frac{1}{2}$ $\mathrm{XXZ}$ chains are studied for general values of p. Two plateau-non-plateau critical lines and one plateau-plateau critical line are found for each value of p. The universality class of the plateau-non-plateau transition belongs to the Brezinskii-Kosterlitz-Thouless type and that of the plateau-plateau transition, to the Gaussian type. The critical points are determined by level spectroscopic analysis of the numerical diagonalization results for $4<~p<~8.$ The multicritical points are calculated using the integral equations based on the Bethe ansatz solution of the $\mathrm{XXZ}$ model. The behavior of multicritical points are analyzed in detail for large p. It is found that the plateau region is enhanced with the increase in periodicity p although the nonplateau region persists as far as p is finite.