Gate-tunable spin-resolved subbands in multilayer WSe2 probed by quantum point contact spectroscopy

TL;DR

This paper demonstrates electric-field control of spin splitting in multilayer WSe2, revealing spin-valley coupling effects and enabling non-magnetic spin manipulation for spintronic and quantum devices.

Contribution

It provides direct experimental evidence of gate-tunable spin-resolved subbands in WSe2 via quantum point contact spectroscopy, highlighting electric-field dominance over magnetic effects.

Findings

Electric-field-induced spin splitting exceeds Zeeman effect.

Four conductance quantization steps show spin-valley-layer coupling.

Gate voltage effectively manipulates spin states in WSe2.

Abstract

Transition metal dichalcogenides provide a platform for exploring spin-valley physics, offering a promising approach to electric-field-driven spin control for low-power spintronic and quantum devices. Here, we demonstrate electric-field-induced spin splitting in the Q and Q' valleys of multilayer n-type WSe2 using quantum-point-contact spectroscopy. Systematic modulations in four distinct conductance quantization steps, providing direct evidence of spin-valley-layer coupling-driven spin-resolved density of states, were achieved by tuning the out-of-plane gate voltage. Notably, the electric-field-induced spin splitting significantly dominated the magnetic-field-induced Zeeman effect (e.g., ~ 6 meV for a displacement field change of ~ 0.04 V/nm vs. ~ 1 meV for a magnetic field of 9 T), demonstrating a powerful, non-magnetic manipulation of spin states. This ability to manipulate spin states by gate voltage is crucial for advancing next-generation low-power spintronic and quantum information technologies.