One-dimensional Heisenberg antiferromagnet in which two S=1/2 and two S=1 spins are arranged alternatively

TL;DR

This paper investigates a one-dimensional Heisenberg antiferromagnet with alternating S=1/2 and S=1 spins, revealing a second-order phase transition with gap vanishing through quantum Monte Carlo and analytical methods.

Contribution

It provides new insights into the phase transition behavior of a specific alternating spin chain using combined numerical and analytical approaches.

Findings

Second-order phase transition observed

Energy gap vanishes at transition point

Ground-state properties characterized

Abstract

Ground-state and thermodynamic properties of the one-dimensional Heisenberg antiferromagnet in which two S=1/2 and two S=1 spins are arranged alternatively are studied by a quantum Monte Carlo method and by analytical estimates. It is found that the ground state of the system undergoes a second-order phase transition which accompanies the vanishing of the energy gap.