Magnetoelectric effects and valley-controlled spinquantum gates in transition metal dichalcogenidebilayers

摘要

In monolayer group-VI transition metal dichalcogenides, charge carriers have spin and valleydegrees of freedom, both associated with magnetic moments. On the other hand, the layerdegree of freedom in multilayers is associated with electrical polarization. Here we show thattransition metal dichalcogenide bilayers offer an unprecedented platform to realize a strongcoupling between the spin, valley and layer pseudospin of holes. Such coupling gives rise tothe spin Hall effect and spin-dependent selection rule for optical transitions in inversionsymmetric bilayer and leads to a variety of magnetoelectric effects permitting quantummanipulation of these electronic degrees of freedom. Oscillating electric and magnetic fieldscan both drive the hole spin resonance where the two fields have valley-dependent interference,making an interplay between the spin and valley as information carriers possible forpotential valley-spintronic applications. We show how to realize quantum gates on the spinqubit controlled by the valley bit.