Physical review. B, Condensed matter
Density-matrix renormalization-group study of the spin-½ XXZ antiferromagnet on the Bethe lattice
Hiromi Otsuka
Abstract
Ground-state properties of a spin-\textonehalf{} $\mathrm{XXZ}$ antiferromagnet on the Bethe lattice with three nearest neighbors are investigated; especially, the nature of the phase transition driven by the anisotropy is examined. In actual calculations, we employ the density-matrix renormalization-group method which is so far used in the studies on the one-dimensional quantum systems; its applicability to the higher-dimensional system is thus exhibited in our calculations. Numerical data on local spin correlations imply that the model undergoes the first-order phase transition at the Heisenberg point ${J}_{\mathrm{xy}}={J}_{z}$ and the ground state is conjectured to be in the Ising-like ordered phase (the ordered phase in $\mathrm{XY}$ plain) for ${J}_{\mathrm{xy}}<{J}_{z}$ (${J}_{\mathrm{xy}}>{J}_{z}$). We also compare our results with those for other systems, say, the $\mathrm{XYZ}$ model on the square lattice to discuss a possible type of symmetry breaking.