Differential Conductance and Quantum Interference in Kondo Systems

TL;DR

This paper develops a large-N theoretical framework to analyze differential conductance in Kondo systems, revealing how quantum interference shapes experimental Fano lineshapes and enables extraction of key physical parameters.

Contribution

It introduces a novel large-N theory for dI/dV in Kondo systems, highlighting the role of quantum interference and providing a method to determine Kondo coupling and tunneling ratios from experiments.

Findings

Quantum interference determines Fano lineshape in dI/dV.

Kondo coupling and tunneling ratios can be extracted from dI/dV.

dI/dV reflects the antiferromagnetic interaction strength.

Abstract

We present a large-N theory for the differential conductance, dI/dV, in Kondo systems measured via scanning tunneling spectroscopy. We demonstrate that quantum interference between tunneling processes into the conduction band and into the magnetic f-electron states is crucial in determining the experimental Fano lineshape of dI/dV. This allows one to uniquely extract the Kondo coupling and the ratio of the tunneling amplitudes from the experimental dI/dV curve. Finally, we show that dI/dV directly reflects the strength of the antiferromagnetic interaction in Kondo lattice systems.