Effect of spin-orbit interaction on circular current: pure spin current phenomena within a ring conductor

Area of Science:

• Condensed Matter Physics
• Quantum Mechanics
• Spintronics

Background:

• Quantum rings can exhibit circulating currents under applied bias.
• Spin-orbit interaction plays a crucial role in spintronic phenomena.

Purpose of the Study:

• To investigate the characteristic features of circular currents in quantum rings with Rashba spin-orbit interaction (RSOI).
• To explore the generation of pure charge and spin currents.
• To demonstrate external control over pure spin currents.

Main Methods:

• Theoretical study of quantum rings under finite bias.
• Analysis of the influence of Rashba spin-orbit interaction (RSOI).
• Examination of different ring-to-leads configurations (symmetric and asymmetric).

Main Results:

• Both charge and spin currents are observed within the quantum ring.
• A pure spin current is achievable at non-zero Fermi energy in symmetric configurations.
• A pure charge current flows at zero Fermi energy in asymmetric configurations, while the spin current vanishes.
• External control over the pure spin current is demonstrated by tuning RSOI.

Conclusions:

• Rashba spin-orbit interaction (RSOI) enables the generation of pure spin circular currents in quantum rings.
• The configuration of ring-to-leads connections dictates the type of current (charge or spin).
• This work provides a new basis for developing highly efficient, low-energy-cost spintronic devices.