Adiabatic Pumping in Interacting Systems

TL;DR

This paper derives a general formula for adiabatic pumping current in interacting systems, extending noninteracting scattering approaches, and demonstrates quantized spin transfer in a two-channel Kondo system.

Contribution

It introduces a new formula for adiabatic pumping in interacting systems and applies it to a two-channel Kondo model to reveal quantized spin transfer.

Findings

Quantized spin of ħ transferred at zero temperature.

Formula generalizes scattering approach for interacting systems.

Finite temperature effects show non-Fermi liquid behavior.

Abstract

A dc current can be pumped through an interacting system by periodically varying two independent parameters such as magnetic field and a gate potential. We present a formula for the adiabatic pumping current in general interacting systems, in terms of instantaneous properties of the system, and find the limits for its applicability. This formula generalizes the scattering approach for noninteracting pumps. We study the pumped spin in a system that exhibits the two-channel Kondo effect as an application of the adiabatic pumping formula. We find that a quantized spin of $\hbar$ is transferred between the two channels as the temperature approaches zero, and discuss the non-Fermi liquid features of this system at finite temperatures.