Colorful points in the XY regime of XXZ quantum magnets

Article

关键词: HEISENBERG-ANTIFERROMAGNET;    TRIANGULAR-LATTICE;    GROUND-STATE;    BETHE-ANSATZ;    NEEL ORDER;   

DOI  :  10.1103/PhysRevB.103.144414

来源: SCIE

【 摘 要 】

In the XY regime of the XXZ Heisenberg model phase diagram, we demonstrate that the origin of magnetically ordered phases is influenced by the presence of solvable points with exact quantum coloring ground states featuring a quantum-classical correspondence. Using exact diagonalization and density matrix renormalization group calculations, for both the square and the triangular lattice magnets, we show that the ordered physics of the solvable points in the extreme XY regime, at J(z)/J(perpendicular to)= -1 and J(z)/J(perpendicular to = )-1/2, respectively, with J(perpendicular to) > 0, adiabatically extends to the more isotropic regime J(z)/J(perpendicular to)similar to 1. We highlight the projective structure of the coloring ground states to compute the correlators in fixed magnetization sectors which enables an understanding of the features in the static spin structure factors and correlation ratios. These findings are contrasted with an anisotropic generalization of the celebrated one-dimensional Majumdar-Ghosh model, which is also found to be (ground-state) solvable. For this model, both exact dimer and three-coloring ground states exist at J(z)/J(perpendicular to)= -1/2 but only the two dimer ground states survive for any J(z)/J(perpendicular to)> -1/2.

【 授权许可】

Free