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

TL;DR

This study uses renormalization group analysis to map the phase diagrams of a spin-1/2 ladder system under staggered magnetic fields and dimerization, revealing critical surface behaviors and symmetry changes.

Contribution

It provides a detailed renormalization group analysis of phase diagrams for the generalized spin-1/2 ladder under external perturbations, highlighting symmetry and critical surface transitions.

Findings

Splitting of SU(2)$_2$ critical line into U(1) and Z$_2$ surfaces under magnetic field.

Merging of critical surfaces into an SU(2)$_1$ surface at high symmetry.

Identification of critical behaviors associated with external field and dimerization.

Abstract

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.