Quantum Monte Carlo study of a nonmagnetic impurity in the two-dimensional Hubbard model

TL;DR

This study uses Quantum Monte Carlo simulations to analyze how a nonmagnetic impurity affects magnetic and electronic properties in the doped two-dimensional Hubbard model, revealing oscillations in the Knight shift related to antiferromagnetic correlations.

Contribution

It provides the first detailed QMC analysis of nonmagnetic impurities in the 2D Hubbard model, linking impurity effects to experimental NMR observations in cuprates.

Findings

Giant oscillations in Knight shift response near impurity

Short-range antiferromagnetic correlations influence impurity effects

Results aid interpretation of NMR data in layered cuprates

Abstract

In order to investigate the effects of nonmagnetic impurities in strongly correlated systems, Quantum Monte Carlo (QMC) simulations have been carried out for the doped two-dimensional Hubbard model with one nonmagnetic impurity. Using a bare impurity potential which is onsite and attractive, magnetic and single-particle properties have been calculated. The QMC results show that giant oscillations develop in the Knight shift response around the impurity site due to the short-range antiferromagnetic correlations. These results are useful for interpreting the NMR data on Li and Zn substituted layered cuprates.