Valley qubit in gated MoS$_2$ monolayer quantum dot

TL;DR

This research proposes a realistic design for a valley qubit in a gated MoS$_2$ monolayer quantum dot, demonstrating electrical control of the valley degree of freedom through simulations.

Contribution

It introduces a detailed modeling approach for a valley qubit in MoS$_2$, including confinement, control, and realistic potential calculations, advancing quantum dot-based qubit technology.

Findings

Successful simulation of electron confinement in a MoS$_2$ quantum dot.

Electrical manipulation of the valley qubit demonstrated via potential modulation.

Realistic modeling confirms feasibility of valley qubit operations.

Abstract

The aim of presented research is to design a nanodevice, based on a MoS$_2$ monolayer, performing operations on a well-defined valley qubit. We show how to confine an electron in a gate induced quantum dot within the monolayer, and to perform the NOT operation on its valley degree of freedom. The operations are carried out all electrically via modulation of the confinement potential by oscillating voltages applied to the local gates. Such quantum dot structure is modeled realistically. Through these simulations we investigate the possibility of realization of a valley qubit in analogy with a realization of the spin qubit. We accurately model the potential inside the nanodevice accounting for proper boundary conditions on the gates and space-dependent materials permittivity by solving the generalized Poisson's equation. The time-evolution of the system is supported by realistic self-consistent Poisson-Schr\"odinger tight-binding calculations. The tight-binding calculations are further confirmed by simulations within the effective continuum model.