Layer- and gate-tunable spin-orbit coupling in a high-mobility few-layer semiconductor.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Spin-orbit coupling (SOC) is a relativistic effect crucial for magnetic, spintronic, and topological phenomena in non-centrosymmetric crystals.
• In bulk materials, SOC strength is typically constant, limiting its application potential.
• Atomically thin materials offer unique properties due to quantum confinement and reduced dimensionality.

Purpose of the Study:

• To investigate and demonstrate tunable spin-orbit coupling (SOC) and intrinsic spin splitting in atomically thin Indium Selenide (InSe).
• To explore the thickness and electric field dependence of SOC in 2D InSe.
• To assess the potential for manipulating SOC for advanced spintronic and topological applications.

Main Methods:

• Utilized quantum oscillation measurements to probe electronic properties and determine SOC parameters.
• Applied an out-of-plane electric field to modulate SOC strength and intrinsic spin splitting.
• Fabricated and characterized atomically thin InSe devices to observe thickness-dependent effects.

Main Results:

• Demonstrated thickness-dependent SOC and intrinsic spin splitting in 2D InSe.
• Showcased continuous tunability of intrinsic spin splitting from 0 to 20 meV via electric field modulation.
• Observed an unexpected order-of-magnitude enhancement of the SOC parameter in certain devices.

Conclusions:

• 2D InSe exhibits extraordinary tunability of spin-orbit coupling, contrasting with bulk materials.
• Electric field control of SOC in InSe offers a pathway for novel spintronic and topological device functionalities.
• The findings pave the way for in operando manipulation of SOC in next-generation electronic devices.