arXiv:cond-mat/0309345 · Physical Review B
Z3 quantum criticality in a spin- 12 chain model
P. Lecheminant, E. Orignac
Abstract
The stability of the magnetization $m=1/3$ plateau phase of the $\mathrm{XXZ}$ spin-$\frac{1}{2}$ Heisenberg chain with competing interactions is investigated upon switching on a staggered transverse magnetic field. Within a bosonization approach, it is shown that the low-energy properties of the model are described by an effective two-dimensional $\mathrm{XY}$ model in a threefold symmetry-breaking field. A phase transition in the three-state Potts universality class is expected separating the $m=1/3$ plateau phase to a phase where the spins are polarized along the staggered magnetic field. The ${Z}_{3}$ critical properties of the transition are determined within the bosonization approach.