Spin-valley Qubits with 2D Transition Metal Dichalcogenides

Recently, theoretical works have explored exploiting spin and valley states in 2D transition metal dichalcogenides (TMDCs) to create electrostatically gated spin-valley qubits. The broken spatial inversion symmetry in... [ view full abstract ]

Recently, theoretical works have explored exploiting spin and valley states in 2D transition metal dichalcogenides (TMDCs) to create electrostatically gated spin-valley qubits. The broken spatial inversion symmetry in monolayer TMDCs and strong spin-valley coupling allow for concurrently valley and spin-polarized charge carriers with long coherence time. Moreover, several zero nuclear spin TMDC isotopes are available to realize a nuclear spin free environment, which is expected to reduce decoherence. Significant progress in the fabrication of electrostatically gated TMDCs have led to the demonstration of single-electron tunnelling in single and double quantum dots in materials such as WS2, MoS2 and WSe2. Continued development in this area will hinge on integrated efforts in material growth and characterization, device design, engineering and modelling. We present our preliminary efforts in fabricating, characterizing and modelling of top-gated TMDC quantum dots. We find that the electrostatic confinement potential is not a straightforward consideration of the gate size and position, but that optimal configurations exist for different geometries. We present measurements of a 2D MoS2  quantum point contact showing conductance steps and peaks indicating quantum confinement.