Long Range Dynamics Related to Magnetic Impurity in the 2D Heisenberg Antiferromagnet

TL;DR

This paper investigates the effects of a magnetic impurity in a 2D Heisenberg antiferromagnet, revealing a Curie law and logarithmic corrections to magnetic susceptibility at low temperatures.

Contribution

It provides a calculation of the logarithmic correction to impurity susceptibility and derives a Ward identity for the impurity-spin-wave vertex in the system.

Findings

Impurity susceptibility follows a Curie law with a logarithmic correction.

Derived a Ward identity relating impurity-spin-wave interactions.

Quantified the low-temperature behavior of magnetic impurities in 2D antiferromagnets.

Abstract

We consider a magnetic impurity in the two-dimensional Heisenberg antifferomagnet with long range antiferromagnetic order. At low temperature the impurity magnetic susceptibility has a Curie term ($\propto 1/T$) and a logarithmic correction ($\propto \ln(T)$). We calculate the correction and derive related Ward identity for the impurity-spin-wave vertex.