Kondo Temperature and High to Low Temperature Crossover in Quantum Dots

TL;DR

This paper redefines the Kondo temperature as a crossover point where quantum and thermal fluctuations balance, using a two-particle self-consistent theory to connect high and low temperature behaviors in quantum dots.

Contribution

It introduces a new perspective on the Kondo temperature as a crossover scale based on electron-hole correlations, differing from the traditional susceptibility-based definition.

Findings

Kondo temperature marks the crossover from Curie-Weiss to Pauli susceptibility.

Quantum fluctuations equal thermal fluctuations at the Kondo crossover.

The theory links high-temperature magnetic behavior to low-temperature quantum effects.

Abstract

Kondo temperature is standardly defined from the local zero-temperature susceptibility in the regime of strong electron correlations as a new scale controlling the low-temperature asymptotics of thermodynamic quantities. We show by using a two-particle self-consistent theory that the Kondo temperature can be identified as a crossover temperature at which the zero-temperature quantum fluctuations equal the thermal ones in the electron-hole correlation function. The high-temperature Curie-Weiss susceptibility is shown to go over to the Pauli one below the Kondo temperature.