Spin polarization of electron current on the quantum well with exchange-splitted levels

TL;DR

This paper investigates how exchange-splitted levels in a quantum well influence spin-dependent backscattering, demonstrating potential for room-temperature spin filtering in ferromagnetic heterostructures.

Contribution

It reveals the spin-dependent backscattering mechanism in quantum wells with exchange-splitted levels, proposing a new method for effective spin filtering at room temperature.

Findings

Backscattering depends on electron spin when levels are in the top QW region.

Spin polarization increases with electric field and electron storage time.

High spin polarization achievable at room temperature.

Abstract

The backscattering process of injected electrons on exchange-splitted levels of quantum well (QW) in ferromagnetic metal / insulator / semiconductor heterostructure is studied. It is found that, if one of the exchange-splitted levels lies in the top region of the QW and the energy of injected electrons is close to the energy of localized electron on this level, the backward scattering becomes dependent on spins of injected electrons. Accumulation of backscattered electrons in the QW leads to considerable reduction of the current depended on its spin orientation. The spin polarization increases with growth of the applied electric field and the storage time of electrons in the QW. High values of the spin polarization can be achieved at room temperature. In this way, the QW with exchange-splitted levels in ferromagnetic metal / insulator / semiconductor heterostructure can be used as effective spin filter.