A two-channel Kondo impurity in the spin-1/2 chain: Consequences for Knight shift experiments

TL;DR

This paper investigates the effects of a magnetic impurity in a spin-1/2 chain, revealing how two-channel Kondo physics can be observed through Knight shift experiments and providing quantitative predictions for experimental detection.

Contribution

It introduces a numerical method to accurately compute local properties near impurities in spin chains, demonstrating observable two-channel Kondo effects in real materials.

Findings

Local susceptibilities exhibit distinctive behavior around impurities.

Quantitative predictions enable experimental detection of two-channel Kondo physics.

Numerical transfer matrix DMRG effectively captures impurity effects in the thermodynamic limit.

Abstract

A magnetic impurity in the spin-1/2 chain is a simple realization of the two-channel Kondo problem since the field theoretical descriptions in the spin-sector are identical. The correlation functions near the impurity can be calculated. Using a modified version of the numerical transfer matrix DMRG, we are able to accurately determine local properties close to the impurity in the thermodynamic limit. The local susceptibilities (Knight-shifts) show an interesting behavior in a large range around the impurities. We are able to make quantitative experimental predictions which would allow to observe two-channel Kondo physics for the first time directly by doping of spin-1/2 chain compounds.