Spin-valley qubit in nanostructures of monolayer semiconductors: Optical control and hyperfine interaction

TL;DR

This paper explores optical control of spin-valley qubits in monolayer TMD nanostructures, analyzing valley hybridization effects, hyperfine interactions, and two-qubit operations for quantum computing applications.

Contribution

It introduces methods for optical manipulation of spin-valley qubits considering different confinement scenarios and examines hyperfine interactions affecting coherence.

Findings

Bulk valley and spin optical selection rules can be preserved in nanostructures.

Hyperfine interactions induce nuclear spin decoherence.

Optical control enables two-qubit operations in quantum dots.

Abstract

We investigate the optical control possibilities of spin-valley qubit carried by single electrons localized in nanostructures of monolayer TMDs, including small quantum dots formed by lateral heterojunction and charged impurities. The quantum controls are discussed when the confinement induces valley hybridization and when the valley hybridization is absent. We show that the bulk valley and spin optical selection rules can be inherited in different forms in the two scenarios, both of which allow the definition of spin-valley qubit with desired optical controllability. We also investigate nuclear spin induced decoherence and quantum control of electron-nuclear spin entanglement via intervalley terms of the hyperfine interaction. Optically controlled two-qubit operations in a single quantum dot are discussed.