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The electronic energy gap and total dipole moment of chemically functionalized hexagonal and triangular graphene quantum dots are investigated by the density functional theory. It has been found that the energy gap can be efficiently tuned…

Mesoscale and Nanoscale Physics · Physics 2018-03-14 Hazem Abdelsalam , Hanan Elhaes , Medhat A. Ibrahim

We theoretically study the optical properties and the electronic structure of highly elongated quantum dots (quantum dashes) and show how carrier trapping due to geometrical fluctuations of the confining potential affects the excitonic…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Piotr Kaczmarkiewicz , Paweł Machnikowski

This article aims to study the linear and nonlinear optical response of inversion symmetric graphene quantum dots (GQDs) in the presence of on-site disorder or vacancies. The presence of disorder or vacancy breaks the special inversion…

Mesoscale and Nanoscale Physics · Physics 2023-10-26 H. K. Avetissian , G. A. Musayelyan , G. F. Mkrtchian

In the present paper, using Pseudo-Quantum Electrodynamics to describe the interaction between electrons in graphene, we investigate the longitudinal and optical conductivities of a neutral graphene sheet near a grounded perfectly…

High Energy Physics - Theory · Physics 2020-09-04 D. C. Pedrelli , D. T. Alves , V. S. Alves

We study the optical properties of hydrogen passivated silicon, germanium and mixed Ge/Si core/shell quantum dots (QDs) using high accuracy Density Functional Theory (DFT) and time-dependent DFT (TDFT). We employ the hybrid DFT functional…

Mesoscale and Nanoscale Physics · Physics 2016-04-19 Shanawer Niaz , Aristides D. Zdetsis , Manzoor Ahmad Badar , Safdar Hussain , Imran Sadiq , Muhammad Aslam Khan

The electronic and optical properties of self-assembled InN/GaN quantum dots (QDs) are investigated by means of a tight-binding model combined with configuration interaction calculations. Tight-binding single particle wave functions are…

Materials Science · Physics 2009-11-11 N. Baer , S. Schulz , P. Gartner , S. Schumacher , G. Czycholl , F. Jahnke

Semiconductor coupled quantum dots provide a unique opportunity of tuning bandgaps by tailoring band offsets, making them ideal for photovoltaic and other applications. Here, we have studied stability, trends in the band gap, band offsets,…

Mesoscale and Nanoscale Physics · Physics 2022-08-16 Arup Chakraborty , Bidisa Das , Indra Dasgupta

We study numerically the optical properties of low-buckled silicene and AB-stacked bilayer graphene quantum dots subjected to an external electric field, which is normal to their surface. Within the tight-binding model, the optical…

Mesoscale and Nanoscale Physics · Physics 2017-08-29 H. Abdelsalam , M. H. Talaat , I. Lukyanchuk , M. E. Portnoi , V. A. Saroka

We investigate an effective low energy theory of HgTe quantum wells near their mass inversion thickness in a perpendicular magnetic field. By comparison of the effective band structure with a more elaborated and well-established model, the…

Mesoscale and Nanoscale Physics · Physics 2009-06-15 M. J. Schmidt , E. G. Novik , M. Kindermann , B. Trauzettel

In this paper we present generic properties of quantum transport in mono-layer graphene. In the scheme of the Kubo-Geenwood formula, we compute the square spreading of wave packets of a given energy with is directly related to conductivity.…

Mesoscale and Nanoscale Physics · Physics 2015-03-19 Guy Trambly de Laissardiere , Didier Mayou

We investigate the effects of wedge disclination on charge carriers in circular graphene quantum dots subjected to a magnetic flux. Using the asymptotic solutions of the energy spectrum for large arguments, we approximate the scattering…

Mesoscale and Nanoscale Physics · Physics 2023-08-09 Ahmed Bouhlal , Ahmed Jellal , Nurisya Mohd Shah

Using 3D k.p calculation including strain and piezoelectricity we predict variation of electronic and optical properties of InAs/GaAs quantum dots (QDs) with the substrate orientation. The QD transition energies are obtained for high index…

Materials Science · Physics 2015-06-25 V. Mlinar , F. M. Peeters

The chapter generalizes results on influence of uniaxial strain and adsorption on the electron states and charge transport or localization in graphene with different configurations of imperfections (point defects): resonant (neutral)…

The unusual electronic properties of single-layer graphene make it a promising material system for fundamental advances in physics, and an attractive platform for new device technologies. Graphene's spin transport properties are expected to…

Mesoscale and Nanoscale Physics · Physics 2009-10-23 Mark B. Lundeberg , Joshua A. Folk

We show that the low temperature electron transport properties of chemically functionalized graphene can be explained as sequential tunneling of charges through a two dimensional array of graphene quantum dots (GQD). Below 15 K, a total…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Daeha Joung , Lei Zhai , Saiful I. Khondaker

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…

Materials Science · Physics 2011-04-19 Deborah Prezzi , Daniele Varsano , Alice Ruini , Elisa Molinari

We study the effects of disorder on bilayer graphene using four different microscopic models and directly compare their results. We compute the self-energy, density of states, and optical conductivity in the presence of short-ranged…

Mesoscale and Nanoscale Physics · Physics 2012-01-27 D. S. L. Abergel , Hongki Min , E. H. Hwang , S. Das Sarma

Linear conductance of junctions formed by graphene flakes with order of nanometer-thick electrodes attached at the corners of the flakes is studied. The explored structures have sizes up to 20000 atoms and the conductance is studied as a…

Mesoscale and Nanoscale Physics · Physics 2015-10-08 Martin Konôpka

Graphene has two atoms per unit cell with quasiparticles exhibiting the Dirac-like behavior. These properties lead to interband in addition to intraband optical transitions and modify the $f$-sum rule on the longitudinal conductivity. The…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 V. P. Gusynin , S. G. Sharapov , J. P. Carbotte

We investigate optical transitions of non-interacting electron systems consisting of two symmetric energy bands touching each other at the Fermi energy (e.g. graphene at half filling). Optical conductivity is obtained using Kubo formula at…

Mesoscale and Nanoscale Physics · Physics 2013-04-03 Ádám Bácsi , Attila Virosztek
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