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arXiv · 2401.06365

Boundary phase transitions of two-dimensional quantum critical XXZ model

Hong-Hao Song·Long Zhang
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Abstract

The boundary critical behavior of the two-dimensional (2D) quantum antiferromagnetic (AF) XXZ model coupled with either a dangling spin-1/2 XXZ chain or a dangling two-leg ladder on the boundary is studied with the bosonization and renormalization group analysis. A rich boundary phase diagram is obtained in each case. In the dangling chain case, the boundary either develops a long-range AF order in the easy-plane or the easy-axis direction with extraordinary critical behavior, or has a valence bond solid order with ordinary boundary critical behavior. In the case of a dangling two-leg ladder, besides the possible easy-plane or easy-axis AF ordered phases on the boundary with extraordinary critical behavior, the boundary can form a singlet phase with ordinary critical behavior without breaking any symmetry. These results are consistent with recent numerical simulations on the boundary critical behavior of 2D quantum spin models.

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Hong-Hao Song, Long Zhang. 2024-01-12. Boundary phase transitions of two-dimensional quantum critical XXZ model. https://doi.org/10.1103/physrevb.111.165139

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