Stability of the Haldane phase in anisotropic magnetic ladders

TL;DR

This paper investigates the stability of the Haldane phase in anisotropic two-leg magnetic ladders with S=1/2 or S=1 spins, using an advanced DMRG method that exploits symmetries to analyze phase boundaries.

Contribution

It introduces a generalized DMRG approach that incorporates symmetries to efficiently study the Haldane phase in anisotropic ladder models.

Findings

Boundaries of the Haldane phase are estimated in the parameter space.

The method allows consideration of more states by reducing matrix dimensions.

The stability of the Haldane phase under anisotropy is characterized.

Abstract

We have considered the properties of anisotropic two-leg ladder models with S=1/2 or S=1 spins on the rungs, using White's density matrix renormalization group method. We have generalized the method by taking into account the symmetries of the model in order to reduce the dimensions of the matrix to be diagonalized, thereby making possible to consider more states. The boundaries in the parameter space of the extended region, where the Haldane phase exists, are estimated.