First-order commensurate-incommensurate magnetic phase transition in the coupled FM spin-1/2 two-leg ladders

TL;DR

This study investigates the magnetic phase transitions in coupled ferromagnetic spin-1/2 two-leg ladders, revealing a first-order commensurate-incommensurate transition and a nonmagnetic ground state, using quantum Monte Carlo simulations.

Contribution

It demonstrates the occurrence of a first-order quantum phase transition in coupled FM ladders due to inter-ladder AFM interactions, a novel insight into their magnetic behavior.

Findings

First-order commensurate-incommensurate transition observed.

Coupled ladders exhibit a nonmagnetic ground state at zero temperature.

Magnetization jumps indicate phase transition.

Abstract

We consider the spin-1/2 two-leg ladders with ferromagnetic (FM) interactions along legs and rungs. Using the stochastic series expansion QMC method, we study the low-temperature magnetic behavior of the system. An isolated spin-1/2 FM two-leg ladder is in the gapped saturated FM phase at zero temperature. As soon as the spin-1/2 FM two-leg ladders are connected with antiferromagnetic (AFM) inter-ladder interaction, a first-order commensurate-incommensurate quantum phase transition occurs in the ground state magnetic phase diagram. In fact a jump in the magnetization curve is observed. We found that, coupled spin-1/2 FM two-leg ladders are in a nonmagnetic phase at zero temperature. Applying a magnetic field, the ground state of coupled spin-1/2 FM two-leg ladders remains in the nonmagnetic phase up to a quantum saturate critical field.