Spin-valley qubits in gated quantum dots in a single layer of transition metal dichalcogenides

TL;DR

This paper presents a detailed microscopic model of spin-valley qubits in gated quantum dots within monolayer transition metal dichalcogenides, highlighting their potential for quantum computing applications.

Contribution

It introduces a multi-million atom tight-binding model to accurately describe spin-valley qubits, incorporating spin-orbit coupling and valley locking effects.

Findings

Identification of degenerate spin-valley qubit states

Demonstration of qubit manipulation via electric fields and valley mixing

Detailed atomistic understanding of qubit properties in TMD quantum dots

Abstract

We develop a microscopic and atomistic theory of electron spin-based qubits in gated quantum dots in a single layer of transition metal dichalcogenides. The qubits are identified with two degenerate locked spin and valley states in a gated quantum dot. The two-qubit states are accurately described using a multi-million atom tight-binding model solved in wavevector space. The spin-valley locking and strong spin-orbit coupling result in two degenerate states, one of the qubit states being spin-down located at the $+K$ valley of the Brillouin zone, and the other state located at the $-K$ valley with spin up. We describe the qubit operations necessary to rotate the spin-valley qubit as a combination of the applied vertical electric field, enabling spin-orbit coupling in a single valley, with a lateral strongly localized valley-mixing gate.