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We present realistic simulations of quantum confinement effects in ballistic graphene quantum dots with linear dimensions of 10 to 40 nm. We determine wavefunctions and energy level statistics in the presence of disorder resulting from edge…
Experimental results obtained previously for the photoluminescence efficiency (PL$_{eff}$) of Ge quantum dots (QDs) are theoretically studied. A $\log$-$\log$ plot of PL$_{eff}$ versus QD diameter ($D$) resulted in an identical slope for…
Graphene is the first truly two-dimensional (2D) material, possessing a cone-like energy spectrum near the Fermi energy and treated as a gapless semiconductor. Its unique properties trigger researchers to find more applications of it, such…
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,…
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…
We show how Dirac electrons interact with a graphene quantum dots (GQDs) when exposed to both a magnetic flux and circularly polarized light. After obtaining the solutions of the energy spectrum, we compute the scattering coefficients.…
In the framework of the perturbative QCD we investigate heavy particle mass effects on the unpolarized and polarized photon structure functions, $F_2^\gamma$ and $g_1^\gamma$, respectively. We present our basic formalism to treat heavy…
The design of some optical devices such as semiconductor optical amplifiers for telecommunication applications requires polarization-insensitive optical emission at the long wavelengths (1300-1550 nm). Self-assembled InAs/GaAs quantum dots…
A distant-neighbor quantum-mechanical method is used to study the nonlinear optical wave mixing in graphene nanoflakes (GNFs), including sum- and difference-frequency generation, as well as four-wave mixing. Our analysis shows that…
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…
We address the spatially nonlocal dielectric functions of graphene at any frequency derived starting fromthe first principles of thermal quantum field theory using the formalism of the polarization tensor. After a brief review of this…
This paper investigates quantum dots (QDs), which are miniature semiconductor structures with remarkable optical and electrical properties due to quantum confinement processes. Traditional QDs, such as CdTe, have been extensively…
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…
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…
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…
Flexoelectricity, polarization induced by strain gradients, is especially pronounced in two-dimensional (2D) materials due to their mechanical flexibility and sensitivity to mechanical deformation. In nanostructures with sub-nm curvature,…
Considering the increasing number of experimental results in the manufacturing process of quantum dots with different geometries, and the fact that most numerical methods that can be used to investigate quantum dots with non-trivial…
We theoretically analyze the thermoelectric properties of graphene quantum dot arrays (GQDAs) with line- or surface-contacted metal electrodes. Such GQDAs are realized as zigzag graphene nanoribbons (ZGNRs) with periodic vacancies. Gaps and…
Graphene is a two-dimensional material with strongly nonlinear electrodynamics and optical properties. We present some of our recent theoretical results on the quantum and non-perturbative quasi-classical theories of nonlinear effects in…
Recently, transition metal dichalcogenides (TMDCs) semiconductors have been utilized for investigating quantum phenomena because of their unique band structures and novel electronic properties. In a quantum dot (QD), electrons are confined…