Spin-dependent pump current and noise in an adiabatic quantum pump based on domain walls in a magnetic nanowire

TL;DR

This paper investigates how adiabatic modulation in a magnetic nanowire with double domain walls affects pump current and noise, revealing peaks at resonant energies and insights into quasiparticle correlations.

Contribution

It introduces a model for spin-dependent pump current and noise in a magnetic nanowire with double domain walls, highlighting the role of resonant levels and side-band formations.

Findings

Pump current peaks at spin-split resonant levels.

Peak height indicates quasistationary state lifetime.

Side-band formations occur for sharp domain walls.

Abstract

We study the pump current and noise properties in an adiabatically modulated magnetic nanowire with double domain walls (DW). The modulation is brought about by applying a slowly oscillating magnetic and electric fields with a controllable phase difference. The pumping mechanism resembles the case of the quantum dot pump with two-oscillating gates. The pump current, shot noise, and heat flow show peaks when the Fermi energy matches with the spin-split resonant levels localized between the DWs. The peak height of the pump current is an indicator for the lifetime of the spin-split quasistationary states between the DWs. For sharp DWs, the energy absorption from the oscillating fields results in side-band formations observable in the pump current. The pump noise carries information on the correlation properties between the nonequilibrium electrons and the quasi-holes created by the oscillating scatterer. The ratio between the pump shot noise and the heat flow serves as an indicator for quasi-particle correlation.