Related papers: Quantum dots in graphene
In this article we discuss confinement of electrons in graphene via smooth magnetic fields which are finite everywhere on the plane. We shall consider two types of magnetic fields leading to systems which are conditionally exactly solvable…
Quantum dots based on the graphene stripes show unconventional optical properties in the THz frequency range. The graphene quantum dot (GQD) is made of electrically gated stripe with zigzag edges. Inside the active region (AR), which is…
Due to Klein tunneling, electrostatic confinement of electrons in graphene is not possible. This hinders the use of graphene for quantum dot applications. Only through quasi-bound states with finite lifetime has one achieved to confine…
In the field of condensed matter, graphene plays a central role as an emerging material for nanoelectronics. Nevertheless, graphene is a semimetal, which constitutes a severe limitation for some future applications. Therefore, a lot of…
Graphene quantum dots are considered as promising alternatives to quantum dots in III-V semiconductors, e.g., for the use as spin qubits due to their consistency made of light atoms including spin-free nuclei which both imply relatively…
We investigate from first principles the electronic and optical properties of edge-modulated armchair graphene nanoribbons, including both quasi-particle corrections and excitonic effects. Exploiting the oscillating behavior of the ribbon…
Due to Klein tunneling in graphene only quasi-bound states are realized in graphene quantum dots by electrostatic gating. Particles in the quasi-bound states are trapped inside the dot for a finite time and they keep bouncing back and forth…
Electrostatically confined quantum dots in bilayer graphene have shown potential as building blocks for quantum technologies. To operate the dots, e.g., as qubits, a precise understanding and control of the confined states and their…
Graphene nanoribbons display an imperfectly understood transport gap. We measure transport through nanoribbon devices of several lengths. In nanoribbons of length greater than or equal to 250 nm we observe transport through multiple quantum…
The existence of bound states in the continuum was predicted at the dawn of quantum mechanics by von Neumann and Wigner. In this work we discuss the mechanism of formation of these exotic states and the feasibility to observe them…
Electronic localization in narrow graphene constrictions is theoretically studied, and it is found that long-lived quasibound states (QBSs) can exist in a class of ultrashort graphene quantum point contacts (QPCs). These QBSs are shown to…
Quantum dots are fabricated in a Ga[Al]As-heterostructure by local oxidation with an atomic force microscope. This technique, in combination with top gate voltages, allows us to generate steep walls at the confining edges and small lateral…
We study electronic and optical properties of single layer phosphorene quantum dots with various shapes, sizes, and edge types (including disordered edges) subjected to an external electric field normal to the structure plane. Compared to…
Graphene is a nonmagnetic semimetal and cannot be directly used as electronic or spintronic devices. We demonstrate that graphene quantum dots (GQDs) can exhibit strong edge magnetism and tunable energy gaps due to the presence of localized…
The electrostatic confinement of massless charge carriers is hampered by Klein tunneling. Circumventing this problem in graphene mainly relies on carving out nanostructures or applying electric displacement fields to open a band gap in…
Laterally localized electronic states are identified on a single layer of graphene on ruthenium. The individual states are separated by 3 nm and comprise regions of about 90 carbon atoms. This constitutes a quantum dot array, evidenced by…
We determine the optical properties of gated bilayer graphene quantum dots with trigonal warping (TW) of single-particle energy spectra. The lateral structure of metallic gates confines electrons and holes in a quantum dot (QD)…
We investigate the controllability of an infinite-dimensional quantum system: a quantum particle confined on a Thick Quantum Graph, a generalisation of Quantum Graphs whose edges are allowed to be manifolds of arbitrary dimension with…
We present a simple technique to fabricate graphene quantum dots in a cryostat. It relies upon the controlled rupture of a suspended graphene sheet subjected to the application of a large electron current. This results in the in-situ…
Electrostatic confinement of charge carriers in bilayer graphene provides a unique platform for carbon-based spin, charge or exchange qubits. By exploiting the possibility to induce a band gap with electrostatic gating, we form a versatile…