Signature of Spin-Resolved Quantum Point Contact in p-Type Trilayer WSe₂ van der Waals Heterostructure

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Quantum point contacts are crucial for understanding quantum transport phenomena.
• Van der Waals heterostructures offer tunable electronic properties.
• Ternary transition metal dichalcogenides are emerging materials for electronic applications.

Purpose of the Study:

• To realize an electrostatically induced quantum point contact in a p-type trilayer tungsten diselenide van der Waals heterostructure.
• To investigate the quantum confinement effects and transport properties of this novel structure.
• To explore the potential for spin-polarized transport in such systems.

Main Methods:

• Fabrication of a p-type trilayer tungsten diselenide van der Waals heterostructure using a modified van der Waals contact method.
• Integration with degenerately doped transition metal dichalcogenide crystals for improved contacts.
• Utilizing dual-gating (split gate electrodes and top gate) for electrostatic control and confinement.
• Measuring conductance and observing quantized plateaus under varying bias conditions.

Main Results:

• Successful realization of an electrostatically induced quantum point contact.
• Observation of clear quantized conductance steps of e²/h.
• Observation of a pinch-off state, confirming one-dimensional confinement.
• Detection of quarter plateaus (0.25 × 2e²/h) at finite bias, indicating intrinsic spin-polarization.

Conclusions:

• The study demonstrates the feasibility of creating quantum point contacts in p-type trilayer WSe2 van der Waals heterostructures.
• The observed quantized conductance and spin-polarized signatures highlight the potential for spintronic applications.
• This work contributes to the development of novel electronic devices based on 2D materials.