Spin-Guide: A New Source of High Spin-Polarized Current

TL;DR

The paper introduces a 'spin-guide' device that efficiently generates and transmits highly spin-polarized currents over long distances in semiconductors, surpassing previous methods in effectiveness.

Contribution

It presents a novel spin-guide scheme that outperforms spin-filter methods, enabling long-distance, high-polarization current transmission even with partially polarized magnetic materials.

Findings

The spin-guide can produce nearly fully spin-polarized currents.

It allows spin polarization to be maintained over distances exceeding the spin-flip length.

The device enables detection and control of current spin-polarization.

Abstract

We propose a ``spin-guide'' source for generation of electric currents with a high degree of spin polarization, allowing long-distance transmission of the spin-polarization. In the spin-guide scheme proposed here, a non-magnetic conducting channel is wrapped by a magnetic shell which preferentially transmits electrons with a particular spin polarization. It is shown that this method is significantly more effective then the spin-filter-like scheme where the current flows perpendicular to the interface between a ferromagnetic metal to a non-magnetic conducting material. Under certain conditions a spin-guide may generate an almost perfectly spin-polarized current, even when the magnetic material used is not fully polarized. The spin-guide is predicted to allow the transport of spin polarization over long distances which may exceed significantly the spin-flip length in the channel. In addition, it readily permits detection and control of the spin-polarization of the current. The spin-guide may be employed for spin-flow manipulations in semiconductors used in spintronic devices.