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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…

Mesoscale and Nanoscale Physics · Physics 2018-08-29 Abdelhadi Belouad , Youness Zahidi , Ahmed Jellal , Hocine Bahlouli

The local density of states (LDOS) in finite quantum wires is calculated as a function of discrete energies and position along the wire. By using a combination of numerical density matrix renormalization group (DMRG) calculations and…

Strongly Correlated Electrons · Physics 2009-11-13 Imke Schneider , Alexander Struck , Michael Bortz , Sebastian Eggert

At the center of quantum computing1 realization is the physical implementation of qubits - two-state quantum information units. The rise of graphene2 has opened a new door to the implementation. Because graphene electrons simulate…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 G. Y. Wu , N. -Y. Lue , L. Chang

We propose a model based on density functional theory (DFT) and quantum electrodynamics (QED) to study the dynamical characteristics of graphene quantum dots (GQDs). We assume the GQD edges are saturated with hydrogen atoms, effectively…

Mesoscale and Nanoscale Physics · Physics 2026-04-09 J. Olivo , J. Blengino Albrieu , Mauro Cuevas

We present a simple derivation of the density of states (DOS) in confined nanomaterials. While previous studies often apply a heuristic $L^{3-d}$ confinement factor to bulk DOS expressions, we show that this factor arises naturally from a…

Quantum Gases · Physics 2026-02-03 Benedick Andrade , Rayda Gammag

We investigate the electrostatic confinement of charge carriers in a gapped graphene quantum dot in the presence of a magnetic flux. The circular quantum dot is defined by an electrostatic gate potential delimited in an infinite graphene…

Mesoscale and Nanoscale Physics · Physics 2021-06-02 Ahmed Bouhlal , Abdelhadi Belouad , Ahmed Jellal , Hocine Bahlouli

The electronic states of an electrostatically confined cylindrical graphene quantum dot and the electric transport through this device are studied theoretically within the continuum Dirac-equation approximation and compared with numerical…

Mesoscale and Nanoscale Physics · Physics 2011-08-12 G. Pal , W. Apel , L. Schweitzer

We report an efficient quantum algorithm for estimating the local density of states (LDOS) on a quantum computer. The LDOS describes the redistribution of energy levels of a quantum system under the influence of a perturbation. Sometimes…

Quantum Physics · Physics 2009-11-10 Joseph Emerson , Seth Lloyd , David Poulin , David Cory

We investigate theoretically the magnetic levels and optical properties of zigzag- and armchair-edged hexagonal graphene quantum dots (GQDs) utilizing the tight-binding method. A new bound edge state at zero energy appears for the zigzag…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Z. Z. Zhang , Kai Chang , F. M. Peeters

We present a calculation of the modulation in the Local Density Of electronic States (LDOS) caused by an impurity in graphene in the presence of external magnetic field. We focus on the spatial Fourier Transform (FT) of this modulation…

Mesoscale and Nanoscale Physics · Physics 2013-05-29 Rudro R. Biswas , A. V. Balatsky

We analyze the bound-state spectra of mass-profile quantum dots in graphene, a system at current experimental reach. Homogeneous perpendicular magnetic fields are also considered which result in breaking the valley degeneracy. The spectra…

Mesoscale and Nanoscale Physics · Physics 2015-04-24 A. Gutiérrez-Rubio , T. Stauber

Dirac fermions interacting with a cylindrically symmetric quantum dot potential created in single and bilayer graphene are not confined but form quasi-bound states. The broadening of these quasi-bound states (i. e. the inverse of their…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 A. Matulis , F. M. Peeters

We present and validate a semi-analytical quasi-normal mode (QNM) theory for the local density of states (LDOS) in coupled photonic crystal (PhC) cavity-waveguide structures. By means of an expansion of the Green's function on one or a few…

Recently, new quantum effects have been studied in thin nano-grating layers. Nano-grating on the surface imposes additional boundary conditions on the electron wave function and reduces the density of states (DOS). When the nano-grating…

Mesoscale and Nanoscale Physics · Physics 2016-05-03 D. Kakulia , A. Tavkhelidze , V. Gogoberidze , M. Mebonia

We report on measurements of the quantum capacitance in graphene as a function of charge carrier density. A resonant LC-circuit giving high sensitivity to small capacitance changes is employed. The density of states, which is directly…

Mesoscale and Nanoscale Physics · Physics 2010-07-28 S. Dröscher , P. Roulleau , F. Molitor , P. Studerus , C. Stampfer , T. Ihn , K. Ensslin

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…

Materials Science · Physics 2017-11-01 Wei Hu , Yi Huang , Lin Lin , Erjun Kan , Xingxing Li , Chao Yang , Jinlong Yang

We examine a graphene quantum dot formed by combining an electric and a uniform magnetic field. The electric field creates a smooth quantum well potential while the magnetic field induces an exponential tail to the dot states. The states…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 G. Giavaras , Franco Nori

We study quantum dots defined by external potentials within finite flakes of bilayer graphene using the tight-binding approach. We find that in the limit of large flakes containing zigzag edges the dot-localized energy levels appear within…

Mesoscale and Nanoscale Physics · Physics 2013-10-21 D. P. Żebrowski , E. Wach , B. Szafran

We study theoretically the energy and spatially resolved local density of states (LDoS) in graphene at high perpendicular magnetic field. For this purpose, we extend from the Schr\"odinger to the Dirac case a semicoherent-state…

Mesoscale and Nanoscale Physics · Physics 2010-07-23 Thierry Champel , Serge Florens

Density functional theory (DFT) and thermal DFT (thDFT) calculations were used to evaluate the energy band structure, bandgap, and the total energy of various graphene quantum dots (GQDs). The DFT calculations were performed using local…

Materials Science · Physics 2021-12-20 Majid Ghandchi , Ghafar Darvish , Mohammad Kazem Moravvej-Farshi