Quantum phase diagram of a spin-1/2 antiferromagnetic chain with magnetic impurity

TL;DR

This paper investigates the complex phase diagram of a spin-1/2 antiferromagnetic chain with magnetic impurity using RG flow analysis, revealing various phases and fixed points depending on coupling strengths.

Contribution

It provides the first detailed RG flow diagram for this model, identifying fixed points and phase behavior influenced by impurity interactions.

Findings

No intermediate stable fixed point in weak coupling phase

Possible stable fixed point at strong coupling phase

Phases include decoupled spins and logarithmic impurity susceptibility

Abstract

We present the renormalization group (RG) flow diagram of a spin-half antiferromagnetic chain with magnetic impurity and one altered link. In this two parameters (competing interactions) model, one can find the complex phase diagram with many interesting fixed points. There is no evidence of intermediate stable fixed point in weak coupling phase. It may arise at the strong coupling phase. Depending on the strength of couplings the phases correspond either to a decoupled spin with Curie law behavior or a logarithmically diverging impurity susceptibility as in the two channel Kondo problem.