Shot noise in ferromagnetic single electron tunneling devices

TL;DR

This paper theoretically investigates frequency-dependent shot noise in ferromagnetic single-electron tunneling devices, revealing spin and charge fluctuation processes, negative differential resistance, and noise enhancement effects.

Contribution

It introduces a detailed analysis of spin and charge fluctuation correlations and their impact on noise characteristics in ferromagnetic tunneling devices.

Findings

Identifies two relaxation processes: low frequency spin and high frequency charge fluctuations.

Shows spin accumulation can cause negative differential resistance.

Demonstrates large spin noise enhances current noise in negative differential resistance regime.

Abstract

Frequency dependent current noise in ferromagnetic double junctions with Coulomb blockade is studied theoretically in the limit of sequential tunneling. Two different relaxation processes are found in the correlations between spin polarized tunneling currents; low frequency spin fluctuations and high frequency charge fluctuations. Spin accumulation in strongly asymmetric junctions is shown to lead to a negative differential resistance. We also show that large spin noise activated in the range of negative differential resistance gives rise to a significant enhancement of the current noise.