Positive cross-correlations in a three-terminal quantum dot with ferromagnetic contacts

TL;DR

This paper investigates how ferromagnetic contacts in a three-terminal quantum dot induce a novel spin blockade, resulting in positive current cross-correlations even without spin accumulation, highlighting a new dynamical spin-dependent transport phenomenon.

Contribution

It introduces the concept of dynamical spin blockade in a three-terminal quantum dot with ferromagnetic contacts and analyzes conditions for its experimental observation.

Findings

Positive zero-frequency cross-correlations due to spin blockade

Influence of spin-flip scattering on current correlations

Optimal conditions for observing the effect

Abstract

We study current fluctuations in an interacting three-terminal quantum dot with ferromagnetic leads. For appropriately polarized contacts, the transport through the dot is governed by a novel dynamical spin blockade, i.e., a spin-dependent bunching of tunneling events not present in the paramagnetic case. This leads for instance to positive zero-frequency cross-correlations of the currents in the output leads even in the absence of spin accumulation on the dot. We include the influence of spin-flip scattering and identify favorable conditions for the experimental observation of this effect with respect to polarization of the contacts and tunneling rates.