Electrotunable artificial molecules based on van der Waals heterostructures

TL;DR

This paper demonstrates the creation of an electrotunable artificial quantum-dot molecule in MoS2 heterostructures, enabling control over single-electron states and exploring spin-valley physics for quantum electronics.

Contribution

It introduces a reversible, gate-controlled artificial molecule in MoS2 heterostructures, a significant advancement over traditional double-quantum-dot systems in 2D materials.

Findings

Successful formation of an artificial quantum-dot molecule in MoS2.

Tunable coupling strength between quantum dots via electrostatic gating.

Observation of Coulomb blockade and weak anti-localization effects.

Abstract

Quantum confinement has made it possible to detect and manipulate single-electron charge and spin states. The recent focus on two-dimensional (2D) materials has attracted significant interests on possible applications to quantum devices, including detecting and manipulating either single-electron charging behavior or spin and valley degrees of freedom. However, the most popular model systems, consisting of tunable double-quantum-dot molecules, are still extremely difficult to realize in these materials. We show that an artificial molecule can be reversibly formed in atomically thin MoS2 sandwiched in hexagonal boron nitride, with each artificial atom controlled separately by electrostatic gating. The extracted values for coupling energies at different regimes indicate a single-electron transport behavior, with the coupling strength between the quantum dots tuned monotonically. Moreover, in the low-density regime, we observe a decrease of the conductance with magnetic field, suggesting the observation of Coulomb blockade weak anti-localization. Our experiments demonstrate for the first time the realization of an artificial quantum-dot molecule in a gated MoS2 van der Waals heterostructure, which could be used to investigate spin-valley physics. The compatibility with large-scale production, gate controllability, electron-hole bipolarity, and new quantum degrees of freedom in the family of 2D materials opens new possibilities for quantum electronics and its applications.