Local magnetic structure due to inhomogeneity of interaction in S=1/2 antiferromagnetic chain

TL;DR

This paper investigates how inhomogeneities in bond interactions affect the local magnetic structure in S=1/2 antiferromagnetic chains, revealing impurity-induced local magnetization and attractive forces between impurities.

Contribution

It provides a detailed analysis of impurity effects on local magnetic properties using quantum Monte Carlo and exact diagonalization methods, focusing on bond-impurity effects in uniform and bond-alternating chains.

Findings

Bond impurities induce local magnetic structures in the chains.

Local magnetization and susceptibility are significantly affected by impurities.

Impurities generally attract each other due to the force analysis.

Abstract

We study the magnetic properties of $S=1/2$ antiferromagnetic Heisenberg chains with inhomogeneity of interaction. Using a quantum Monte Carlo method and an exact diagonalization method, we study bond-impurity effect in the uniform $S=1/2$ chain and also in the bond-alternating chain. Here `bond impurity' means a bond with strength different from those in the bulk or a defect in the alternating order. Local magnetic structures induced by bond impurities are investigated both in the ground state and at finite temperatures, calculating the local magnetization, the local susceptibility and the local field susceptibility. We also investigate the force acting between bond impurities and find the force generally attractive.