Spin polarization gate device based on the chirality-induced spin selectivity and robust nonlocal spin polarization

TL;DR

This paper investigates nonlocal spin polarization in chiral crystal devices, demonstrating controllable spin switching via charge current injection, and proposes a model explaining the long-range spin effects with potential for large-area spin control.

Contribution

It introduces a novel nonlocal spin polarization device based on chirality-induced effects, with experimental validation and a theoretical model explaining long-range spin phenomena.

Findings

Nonlocal spin polarization occurs regardless of material differences.

Simultaneous charge injection induces controllable spin switching.

The model successfully explains experimental data.

Abstract

Nonlocal spin polarization phenomena are thoroughly investigated in the devices made of chiral metallic single crystals of CrNb$_3$S$_6$ and NbSi$_2$ as well as of polycrystalline NbSi$_2$. We demonstrate that simultaneous injection of charge currents in the opposite ends of the device with the nonlocal setup induces the switching behavior of spin polarization in a controllable manner. Such a nonlocal spin polarization appears regardless of the difference in the materials and device dimensions, implying that the current injection in the nonlocal configuration splits spin-dependent chemical potentials throughout the chiral crystal even though the current is injected into only a part of the crystal. We show that the proposed model of the spin dependent chemical potentials explains the experimental data successfully. The nonlocal double-injection device may offer significant potential to control the spin polarization to large areas because of the nature of long-range nonlocal spin polarization in chiral materials.