Spontaneous spin polarized tunneling current through a quantum dot array

TL;DR

This paper theoretically demonstrates that a quantum dot array can generate a highly spin-polarized tunneling current, acting as a spin filter for quantum information applications, by exploiting ferromagnetic phases induced by Coulomb interactions.

Contribution

It introduces a theoretical model showing how ferromagnetic phases in quantum dot arrays enable spin-polarized tunneling currents, useful for spintronic devices.

Findings

Ferromagnetic phase exists within a specific gate voltage window.

Quantum dot array can serve as an effective spin filter.

Strong Coulomb repulsion and weak interdot coupling are key factors.

Abstract

We show theoretically that a strongly spin-polarized current can be generated in semiconductors by taking advantage of the ferromagnetic phase of a quantum dot array (QDA). A Hubbard model with coupling to leads is used to study the tunneling current of the QDA system as a function of gate voltage. Due to the weak interdot coupling and strong Coulomb repulsion, it is found that a ferromagnetic phase exists in QDA within a window of gate voltage. Therefore QDA can be used as a spin filter to detect and control spin states in quantum information devices.