Defects in Heavy-Fermion Materials: Unveiling Strong Correlations in Real Space

TL;DR

This paper presents a microscopic theoretical framework showing how defects in heavy-fermion materials reveal complex competing interactions and correlations in real space, aiding understanding of their non-Fermi-liquid behavior.

Contribution

It introduces a novel approach to visualize and analyze impurity-induced electronic and magnetic correlations in heavy-fermion systems.

Findings

Defect-induced spatial patterns differ in electronic and magnetic correlations.

Spectroscopic signatures reveal the nature of perturbed states.

Quantum interference effects can induce phase transitions.

Abstract

Complexity in materials often arises from competing interactions at the atomic length scale. One such example are the strongly correlated heavy-fermion materials where the competition between Kondo screening and antiferromagnetic ordering is believed to be the origin of their puzzling non-Fermi-liquid properties. Insight into such complex physical behavior in strongly correlated electron systems can be gained by impurity doping. Here, we develop a microscopic theoretical framework to demonstrate that defects implanted in heavy-fermion materials provide an opportunity for unveiling competing interactions and their correlations in real space. Defect-induced perturbations in the electronic and magnetic correlations possess characteristically different spatial patterns that can be visualized via their spectroscopic signatures in the local density of states or non-local spin susceptibility. These real space patterns provide insight into the complex electronic structure of heavy-fermion materials, the light or heavy character of the perturbed states, and the hybridization between them. The strongly correlated nature of these materials also manifests itself in highly non-linear quantum interference effects between defects that can drive the system through a first-order phase transition to a novel inhomogeneous ground state.