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

Area of Science:

• Condensed matter physics
• Materials science
• Spintronics

Background:

• Nonlocal spin polarization is a key phenomenon in spintronics.
• Chiral materials offer unique spin-dependent properties.
• Controlling spin polarization over large areas is a significant challenge.

Purpose of the Study:

• To investigate nonlocal spin polarization phenomena in chiral metallic single crystals (CrNb3S6, NbSi2) and polycrystalline NbSi2.
• To demonstrate controllable switching of spin polarization using a nonlocal setup.
• To understand the underlying mechanism of nonlocal spin polarization in chiral materials.

Main Methods:

• Fabrication of devices using CrNb3S6, NbSi2 single crystals, and polycrystalline NbSi2.
• Utilizing a nonlocal electrical measurement setup.
• Simultaneous injection of charge currents at opposite ends of the devices.
• Developing and applying a model of spin-dependent chemical potentials.

Main Results:

• Demonstrated controllable switching of nonlocal spin polarization.
• Observed consistent nonlocal spin polarization across different materials and device dimensions.
• Showed that current injection splits spin-dependent chemical potentials throughout the chiral crystal.
• Validated the proposed model with experimental data.

Conclusions:

• Nonlocal spin polarization is a robust phenomenon in chiral materials, controllable via current injection.
• The observed effects are attributed to the splitting of spin-dependent chemical potentials.
• The nonlocal double-injection device shows potential for large-area spin polarization control in chiral materials.