Electron Cotunneling into a Kondo Lattice

TL;DR

This paper develops a theoretical model for electron tunneling into a Kondo lattice, revealing how cotunneling and disorder influence the tunneling conductance and produce characteristic spectral features.

Contribution

It introduces a large-N mean field theory to describe tunneling into a Kondo lattice, including effects of disorder on the conductance spectrum.

Findings

Differential conductance shows two peaks separated by the hybridization gap.

Disorder causes smearing of the gap and results in a Fano lineshape.

The theory aligns with recent experimental observations.

Abstract

Motivated by recent experimental interest in tunneling into heavy electron materials, we present a theory for electron tunneling into a Kondo lattice. The passage of an electron into the Kondo lattice is accompanied by a simultaneous spin flip of the localized moments via cotunneling mechanism. We compute the tunneling current with the large-$N$ mean field theory. In the absence of disorder, differential tunneling conductance exhibits two peaks separated by the hybridization gap. Disorder effects lead to the smearing of the gap resulting in a Fano lineshape.