Quantum criticalities in a two-leg antiferromagnetic S=1/2 ladder induced by a staggered magnetic field

Article

关键词: ISOTROPIC HEISENBERG CHAIN;    EXACT FORM-FACTORS;    SINE-GORDON MODEL;    INDUCED GAP;    CRITICAL EXPONENTS;    ISING-MODEL;    SPIN-LIQUID;    EXCITATIONS;    TRANSITIONS;    CONTINUUM;   

DOI  :  10.1103/PhysRevB.66.024412

来源: SCIE

【 摘 要 】

We study a two-leg antiferromagnetic spin-1/2 ladder in the presence of a staggered magnetic field. We consider two parameter regimes: strong (weak) coupling along the legs and weak (strong) coupling along the rungs. In both cases, the staggered field drives the Haldane spin-liquid phase of the ladder towards a Gaussian quantum criticality. In a generalized spin ladder with a non-Haldane, spontaneously dimerized phase, the staggered magnetic field induces an Ising quantum critical regime. In the vicinity of the critical lines, we derive low-energy effective field theories and use these descriptions to determine the dynamical response functions, the staggered spin susceptibility, and the string order parameter.

【 授权许可】

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