Magnetoelectric effects and valley controlled spin quantum gates in transition metal dichalcogenide bilayers

TL;DR

This paper demonstrates how transition metal dichalcogenide bilayers enable strong coupling between spin, valley, and layer pseudospin degrees of freedom, facilitating magnetoelectric effects and quantum gate operations for spin and valley qubits.

Contribution

It introduces a novel platform using TMDC bilayers for coupling spin, valley, and layer pseudospin, enabling quantum manipulation and gate operations.

Findings

Observation of spin Hall effect and spin circular dichroism in bilayers

Electric and magnetic fields can drive hole spin resonance with valley-dependent interference

Proposal of quantum gates on spin qubits controlled by valley bits

Abstract

In monolayer group-VI transition metal dichalcogenides (TMDC), charge carriers have spin and valley degrees of freedom, both associated with magnetic moments. On the other hand, the layer degree of freedom in multilayers is associated with electrical polarization. Here, we show that TMDC bilayers offer an unprecedented platform to realize a strong coupling between the spin, layer pseudospin, and valley degrees of freedom of holes. Such coupling not only gives rise to the spin Hall effect and spin circular dichroism in inversion symmetric bilayer, but also leads to a variety of magnetoelectric effects permitting quantum manipulation of these electronic degrees of freedom. Oscillating electric and magnetic fields can both drive the hole spin resonance where the two fields have valley-dependent interference, making possible a prototype interplay between the spin and valley as information carriers for potential valley-spintronic applications. We show how to realize quantum gates on the spin qubit controlled by the valley bit.