Spin correlations in spin blockade

TL;DR

This paper studies spin currents and their correlations in double quantum dots under spin blockade, analyzing fluctuations, effects of ac fields, and revealing super-Poissonian behavior in charge and spin currents.

Contribution

It provides a detailed analysis of spin-resolved currents and their fluctuations in spin blockade, including effects of ac fields causing spin rotation and photon-assisted tunnelling.

Findings

Charge and spin currents are generally super-Poissonian.

Ac fields induce spin rotation and photon-assisted tunnelling effects.

Derived expressions for current fluctuations and correlations.

Abstract

We investigate spin currents and spin-current correlations for double quantum dots in the spin blockade regime. By analysing the time evolution of the density matrix, we obtain the spin resolved currents and derive from a generating function an expression for the fluctuations and correlations. Both the charge current and the spin current turn out to be generally super-Poissonian. Moreover, we study the influence of ac fields acting upon the transported electrons. In particular, we focus on fields that cause spin rotation or photon-assisted tunnelling.