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Graphene quantum dots (GQDs) not only have potential applications on spin qubit,but also serve as essential platforms to study the fundamental properties of Dirac fermions, such as Klein tunneling and Berry phase. By now, the study of…

Mesoscale and Nanoscale Physics · Physics 2021-11-24 Si-Yu Li , Lin He

We present time-dependent density functional theory (TDDFT) calculations of fluorescence emission energies for 284 distinct graphene quantum dots (GQDs) of varying shapes (square, hexagonal, and amorphous) and sizes ($\sim$1-2 nm). These…

Materials Science · Physics 2024-10-22 Mustafa Çoşkun Özdemir , Caner Ünlü , Şener Özönder

The band modulation of the silicene and graphene quantum dots is investigated by a first-principles method. This study includes the ordinary silicene and graphene quantum dots and the embedded quantum dots in the hydrogenated silicene and…

Mesoscale and Nanoscale Physics · Physics 2018-12-24 Bi-Ru Wu

Graphene quantum dots (GQD) are interesting materials due to the confined sizes which allow to exploit their optoelectronic properties, especially when they interface with organic molecules through physisorption. In particular, when…

Materials Science · Physics 2019-10-23 Silvio Osella , Stefan Knippenberg

We report on time-dependent density functional theory (TDDFT) calculations of the excited states of 63 different graphene quantum dots (GQDs) in square shape with side lengths 1 nm, 1.5 nm and 2 nm. We investigate the systematics and trends…

Chemical Physics · Physics 2022-06-07 Şener Özönder , Caner Ünlü , Cihat Güleryüz , Levent Trabzon

Employing a combination of many-body configuration interaction method described by extended Hubbard model along with first principle calculations we predict the emergence of high oscillator strength at near-IR region which originates from…

Materials Science · Physics 2016-11-15 Madhuri Mukhopadhyay , Bradraj Pandey , Swapan K Pati

We analyse the electronic and optical properties of graphene quantum dots (GQD) using accurate \textit{ab initio} many-body $GW$ and Bethe-Salpeter calculations. We show that most pristine GQD, including structures with irregular shapes,…

Mesoscale and Nanoscale Physics · Physics 2020-03-26 Denis M. Basko , Ivan Duchemin , Xavier Blase

We determine the optimum topology of quasi-one dimensional nonlinear optical structures using generalized quantum graph models. Quantum graphs are relational graphs endowed with a metric and a multiparticle Hamiltonian acting on the edges,…

Quantum Physics · Physics 2015-06-19 Rick Lytel , Shoresh Shafei , Mark G. Kuzyk

A few years ago, by means of first-principles calculations, Enyashin et al.(2011) proposed several novel monolayers of carbon containing rings other than hexagons. One of those monolayers containing tetragons and octagons was investigated…

Materials Science · Physics 2025-06-26 Arifa Nazir , Alok Shukla

A semiconductor quantum dot (QD) can generate highly indistinguishable single-photons at a high rate. For application in quantum communication and integration in hybrid systems, control of the QD optical properties is essential.…

In this paper, optical and electronic properties of diamond shaped graphene quantum dots (DQDs) have been studied by employing large-scale electron-correlated calculations. The computations have been performed using the \pi-electron…

Mesoscale and Nanoscale Physics · Physics 2015-11-16 Tista Basak , Himanshu Chakraborty , Alok Shukla

We demonstrate theoretically that quantum dots in bilayers of graphene can be realized. A position-dependent doping breaks the equivalence between the upper and lower layer and lifts the degeneracy of the positive and negative momentum…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 J. Milton Pereira , P. Vasilopoulos , F. M. Peeters

Graphene quantum dots (GQDs) are more promising than other kinds of semiconductor QDs because of their photostability and biocompatibility in different applications such as bioimaging, biosensing and light emitting diodes (LEDs). In…

Density functional theory (DFT) can be quite advantageous in advancing the field of catalysis because of the microscopic insights it provides, and thus can guide experimental searches of novel catalysts. Several recent works have…

Materials Science · Physics 2022-03-24 Vaishali Sharma , Basant Roondhe , Sumit Saxena , Alok Shukla

Optical non-linearities usually appear for large intensities, but discrete transitions allow for giant non-linearities operating at the single photon level. This has been demonstrated in the last decade for a single optical mode with cold…

Owing to its peculiar energy dispersion, the quantum capacitance property of graphene can be exploited in a two-dimensional layered capacitor configuration. Using graphene and boron nitride respectively as the electrodes and the insulating…

Quantum Physics · Physics 2017-05-19 Sina Khorasani , Akshay Koottandavida

Quantum networking technologies use spin qubits and their interface to single photons as core components of a network node. This necessitates the ability to co-design the magnetic- and optical-dipole response of a quantum system. These…

With recent advances in strain-engineering technology of graphene and 2D materials, graphene quantum dots (QDs) defined by the strain-induced pseudo-magnetic fields (PMFs) have been of interest, with the feasibility of tunable graphene…

Mesoscale and Nanoscale Physics · Physics 2025-11-03 Myung-Chul Jung , Nojoon Myoung

The linear electrodynamic properties of graphene -- the frequency-dependent conductivity, the transmission spectra and collective excitations -- are briefly outlined. The non-linear frequency multiplication effects in graphene are studied,…

Mesoscale and Nanoscale Physics · Physics 2009-05-27 S. A. Mikhailov

We theoretically investigate the effects of long-range disorder and electron-electron interactions on the optical properties of hexagonal armchair graphene quantum dots consisting of up to 10806 atoms. The numerical calculations are…

Mesoscale and Nanoscale Physics · Physics 2017-02-08 A. Altıntaş , K. E. Çakmak , A. D. Güçlü