Synthetic Rashba spin-orbit system using a silicon metal-oxide semiconductor

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Spin-orbit interaction (SOI) is crucial for manipulating spin degrees of freedom, typically observed in heavy elements.
• Silicon (Si) is a light element with inherent lattice inversion symmetry, leading to negligible bulk SOI.
• The development of novel SOI systems is essential for advancing spintronics.

Purpose of the Study:

• To investigate the presence and characteristics of Rashba-type SOI in silicon metal-oxide-semiconductor (MOS) heterostructures.
• To explore the tunability of SOI in silicon using external gate electric fields.
• To establish silicon-based systems as a viable platform for spin-orbit phenomena.

Main Methods:

• Fabrication of silicon MOS heterostructures.
• Application of a strong gate electric field across the heterostructure.
• Measurement of spin lifetime anisotropy of propagating spins in silicon.

Main Results:

• Observation of Rashba-type SOI in silicon MOS heterostructures, contrary to expectations for light elements.
• Formation of an emergent effective magnetic field due to SOI, leading to spin lifetime anisotropy.
• Gate-tunable Rashba parameter (α) increasing linearly with the applied electric field, reaching 9.8 × 10⁻¹⁶ eV m at 0.5 V nm⁻¹.
• Achieved a relatively large spin splitting of 0.6 μeV.

Conclusions:

• Silicon MOS heterostructures exhibit significant and tunable Rashba-type spin-orbit interaction.
• This work demonstrates a new class of spin-orbit systems based on silicon.
• The findings open avenues for developing novel spintronic devices utilizing silicon technology.