Spin Current Through a Magnetic-Oscillating Quantum Dot

TL;DR

This paper investigates how a precessing magnetic field influences spin transport through an interacting quantum dot, revealing resonance effects and enhanced spin currents due to the Kondo effect.

Contribution

It demonstrates the impact of magnetic precession on Kondo resonance splitting and spin current enhancement in quantum dots, a novel insight into spintronics.

Findings

Kondo resonance splits into two peaks at resonance frequency.

Large enhancement of spin current in strong coupling, low temperature regime.

Precessing magnetic field significantly modifies Kondo effect.

Abstract

Non-equilibrium spin transport through an interacting quantum dot is analyzed. The coherent spin oscillations in the dot provide a generating source for spin current. In the interacting regime, the Kondo effect is influenced in a significant way by the presence of the precessing magnetic field. In particular, when the precession frequency is tuned to resonance between spin up and spin down states of the dot, Kondo singularity for each spin splits into a superposition of two resonance peaks. The Kondo-type cotunneling contribution is manifested by a large enhancement of the pumped spin current in the strong coupling, low temperature regime.