Valley spin polarization by using the extraordinary Rashba effect on silicon

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Next-generation electronic devices can benefit from incorporating the valley degree of freedom into spin-polarized systems.
• Activating this valley degree of freedom requires polarizing the valleys, a significant challenge that has hindered device realization.

Purpose of the Study:

• To demonstrate a simple and effective method for achieving 100% spin-polarized valleys.
• To explore the potential of such polarized valleys in suppressing spin-charge backscattering.
• To pave the way for efficient silicon spintronic devices.

Main Methods:

• Utilizing the Rashba effect on a system with C3 symmetry.
• Investigating the polarization of valleys in a two-dimensional spin-polarized electronic system.
• Fabricating the system on a silicon substrate.

Main Results:

• Achieved 100% spin-polarized valleys, significantly higher than in typical Rashba systems.
• Demonstrated that these polarized valleys function as effective filters, suppressing spin-charge backscattering.
• Successfully developed the system on a silicon substrate.

Conclusions:

• The developed method provides a straightforward route to high-efficiency valley polarization.
• The observed suppression of backscattering by polarized valleys offers a new mechanism for spintronic applications.
• This work opens promising avenues for the development of advanced silicon spintronic devices.