Gate‐Controlled Quantum Dots Based on 2D Materials

Abstract

Two-dimensional (2D) materials are a family of layered materials exhibiting rich exotic phenomena, such as valleycontrasting physics. Down to single-particle level, unraveling fundamental physics and potential applications including quantum information processing in these materials attracts significant research interests. To unlock these great potentials, gate-controlled quantum dot architectures have been applied in 2D materials and their heterostructures. Such systems provide the possibility of electrical confinement, control, and manipulation of single carriers in these materials. In this review, efforts in gate-controlled quantum dots in 2D materials are presented. Following basic introductions to valley degree of freedom and gate-controlled quantum dot systems, the up-to-date progress in etched and gate-defined quantum dots in 2D materials, especially in graphene and transition metal dichalcogenides, is provided. The challenges and opportunities for future developments in this field, from views of device design, fabrication scheme, and control technology, are discussed. The rapid progress in this field not only sheds light on the understanding of spin-valley physics, but also provides an ideal platform for investigating diverse condensed matter physics phenomena and realizing quantum computation in the 2D limit.

A simplified Mølmer–Sørensen gate for the trapped ion quantum computer

“…This characteristic is a complete contrast to that of the curves in figure 2. Thus, we can conclude that the two-qubit gate caused by the Hamiltonian defined by equation (35) is not well protected from thermal fluctuations of the phonons.…”

“…In [35], experimental demonstrations of gate-controlled quantum dots based on two-dimensional materials were discussed. According to [35], experiments of quantum dots for quantum computation also require the temperature of the system to be kept low enough. where T ge = T ge (n, Ω, ν, Δν, η), and T ge is on the order of ν/Ω 2 .…”

Dielectrics for Two-Dimensional Transition-Metal Dichalcogenide Applications

“…Recently, 2D materials have emerged as qubit candidates; their atomically thin geometry presents natural carrier confinement along the out-of-plane dimension and improved electrostatics that facilitate carrier confinement. − While current state-of-the-art 2D material-based quantum dot demonstrations are mostly on graphene, , 2D TMD semiconductors offer many enticing upgrades. − 2D TMDs have direct band-gaps; unlike graphene which requires additional fabrication complexity to induce a bandgap, e.g., with atomically precise edges or perpendicular electric fields. Due to the d orbital electrons in the metal atoms, TMDs have strong spin–orbit coupling useful for fast, all-electrical qubit control via electric dipole spin resonance.…”

Controlled Emission of Entangled Multiphoton States from Cascaded Quantum Wells

“…Since the decoherence time is the most problematic parameter to cope with, we envision that the realization using longer-lived qubits (nano-to microseconds) will be much more optimal. Superconducting qubits, self-assembled stacked semiconductor quantum dots (at a low density, so that a single stack can be isolated), 48 quantum dot molecules, 49 and especially voltage-induced (gate-controlled) quantum dot molecules in semiconductor 50 or 2D materials 51 have by orders of magnitude longer coherence times, and the remaining challenge will be the precise engineering of the cascaded structure. The control of the potential well parameters by applying prescribed voltages makes such a cascaded quantum-dot molecule a recommended realization to consider.…”