Continuous phase transition from Neel state to Z(2) spin-liquid state on a square lattice

Article

关键词: LARGE-N EXPANSION;    QUANTUM ANTIFERROMAGNETS;    SUPERCONDUCTIVITY;    INSULATOR;    MAGNETISM;    PHYSICS;    MODEL;   

DOI  :  10.1103/PhysRevB.89.235122

来源: SCIE

【 摘 要 】

Recent numerical studies of the J(1)-J(2) model on a square lattice suggest a possible continuous phase transition between the Neel state and a gapped spin-liquid state with Z(2) topological order. We show that such a phase transition can be realized through two steps: First bring the Neel state to the U(1) deconfined quantum critical point, which has been studied in the context of Neel-valence bond solid (VBS) state phase transition. Then condense the spinon pair-skyrmion/antiskyrmion bound state, which carries both gauge charge and flux of the U(1) gauge field emerging at the deconfined quantum critical point. We also propose a Schwinger boson projective wave function to realize such a Z(2) spin liquid state and find that it has a relatively low variational energy (-0.4893J(1)/site) for the J(1)-J(2) model at J(2) = 0.5J(1). The spin liquid state we obtain breaks the fourfold rotational symmetry of the square lattice and therefore is a nematic spin liquid state. This direct continuous phase transition from the Neel state to a spin liquid state may be realized in the J(1)-J(2) model, or the anisotropic J(1x)-J(1y)-J(2) model.

【 授权许可】

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