Effective Landé factors for an electrostatically defined quantum point contact in silicene

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Quantum point contacts (QPCs) are crucial for understanding electron transport in low-dimensional systems.
• Silicene, a silicon analog of graphene, exhibits strong spin-orbit coupling due to its buckled structure.
• The Landé g-factor is a fundamental property characterizing the magnetic moment of electrons.

Purpose of the Study:

• To investigate the transconductance and effective Landé g-factors of a QPC in silicene.
• To analyze the influence of electric fields from split gates on these properties.
• To understand the role of spin-orbit coupling in modifying g-factors under various magnetic field orientations.

Main Methods:

• Theoretical investigation of a quantum point contact defined in silicene.
• Utilizing split-gate electric fields to define the QPC.
• Analysis of Landé g-factors under in-plane and perpendicular magnetic fields.
• Considering silicene nanoribbons with zigzag and armchair edges.

Main Results:

• Strong spin-orbit coupling in buckled silicene reduces the in-plane g-factor from 2 to 1.2 (first subband) and 0.45 (third subband).
• Perpendicular magnetic fields enhance g-factors, reaching 5.8 for zigzag and 2.5 for armchair edges in the first subband.
• Intrinsic spin-orbit coupling (Kane-Mele form) is the primary contributor to Zeeman splitting.

Conclusions:

• Silicene's strong spin-orbit coupling significantly modifies Landé g-factors in QPCs.
• The orientation of the magnetic field and the edge type of silicene nanoribbons critically influence g-factor values.
• The findings highlight the potential of silicene for spintronic applications.