Phase diagrams of the generalized spin-1/2 ladder under staggered field and dimerization: A renormalization-group study

[摘要] In the weak-coupling regime of the continuous theories, two sets of one-loop renormalization-group equations are derived and solved to disclose the phase diagrams of the antiferromagnetic generalized two-leg spin-1/2 ladder under the effect of (I) a staggered external magnetic field and (II) an explicit dimerization. In model (I), the splitting of the SU(2)(2) critical line into U(1) and Z(2) critical surfaces is observed, while in model (II), two critical surfaces arising from their underlying critical lines with SU(2)(2) and Z(2) characteristics merge into an SU(2)(1) critical surface on the line where the model attains its highest symmetry.

[发布日期] 2003-12-01

[关键词] EXCITATIONS;EXCHANGE;LIQUID;MODEL