We present first-principles calculations of electronic properties graphene under uniaxial and isotropic strains, respectively. The semi-metallic nature is shown to persist up a very large strain 30% except narrow range where tiny energy gap opens. As the increases along certain direction, Fermi velocity parallel it decreases quickly vanishes eventually, whereas perpendicular by as much 25%. Thus, low with small strains can be described generalized Weyl's equation while massless massive...

Quantum dots (QD) are regarded as ideal light emitters for current and next-generation displays. Hence, there is an urgent need to produce environmentally friendly QDs that show high efficiency better color purity. From this perspective, a strategy of tuning the wavelength spectral width discussed optimize brightness space agreement. The critical parameters affecting photophysical properties, such uniformity InP QD core, thickness shape ZnSe shell, electron/hole distribution, surface...

Using the first principles calculations, we show that mechanically tunable electronic energy gap is realizable in bilayer graphene if different homogeneous strains are applied to two layers. It shown size of can be simply controlled by adjusting strength and direction these strains. We also effect originates from occurrence strain-induced pseudoscalar potentials graphene. When with strengths each layer graphene, transverse electric fields across layers generated without any external sources,...

The adsorption of alkali metals (AMs) on single layer graphene is studied using first principles methods. We observe a common trend in the binding distance, charge transfer, and work function $(W)$ at certain coverage AMs with increase proportion $\ensuremath{\rho}$ (adatom/C atom) covered by AM. A dip these properties occurs $\ensuremath{\rho}\ensuremath{\approx}0.04$ for all except Li, which it $\ensuremath{\rho}\ensuremath{\approx}0.08$. This behavior due to transition adsorbed from...

The colloidal quantum dots (QDs) have inherent multiple dangling bonds (DBs) on the surface atoms due to intrinsic weak bonding nature and steric hindrance of organic ligands. Such DBs can be trap sites for charge carriers, leading reduction luminescence efficiency, but their detailed characteristics are still unclear. In this study, we disclose electronic optical features InP QDs via density functional calculations combined with experimental evidence. For core, both In-DB P-DB create...

Electronic and magnetic properties of alkali alkaline-earth metal doped graphene nanoribbons (GNRs) are studied by the pseudopotential density functional method. Strong site dependence is observed in adsorption on GNRs, adsorbed atoms found to spontaneously form atomic chains a particular GNRs. Such GNRs exhibit intriguing such as hysteresis spin compensation switch from one edge another at alternating gate voltages. Our study shows that can be used reagents identify structures also...

We demonstrate theoretically that the topology of energy bands and Fermi surface in bilayer graphene undergoes a very sensitive transition when an extremely tiny lateral interlayer shift occurs arbitrary directions. The phenomenon originates from generation effective non-Abelian vector potential Dirac Hamiltonian by sliding motions. characteristics such as pair annihilations massless fermions are dictated direction owing to unique interplay between gauge fields Berry's phases associated with...

To obtain highly efficient, stable, and environmentally friendly blue-light-emitting materials for display applications, we prepared a specially tailored Cd-free, colloidal quantum-well (CQW) structure of ZnS/ZnTeSe/ZnS. We optimized the synthetic methods to construct very uniform ZnS core having diameter ∼2.9 nm within 10% size distribution. In addition, it was found that QD structures were either cube with (100) surface facets or tetrahedron (111) facets. As ZnTeSe mid-shell grew on...

The electronic structure of Na-adsorbed graphenes formed on the 6H-SiC(0001) substrate was studied using angle-resolved photoemission spectroscopy with synchrotron photons and ab initio pseudopotential calculations. It found that band sensitively changes upon Na adsorption especially at low temperature. With increasing dose, $\ensuremath{\pi}$ appears to be quickly diffused into background 85 K whereas it becomes significantly enhanced its spectral intensity room temperature (RT). A new...

The electronic property of epitaxial graphenes with Na adsorption or intercalation is studied the use pseudopotential density functional method. It found that charge transfer and binding energy show strong coverage dependence. Calculated energetics shows prefers between buffer top graphene layers to on layer. layer inert but it charged when atoms are intercalated. This indicates conduction can be affected significantly by intercalation.

Thermoelectric device is a promising next-generation energy solution owing to its capability transform waste heat into useful electric energy, which can be realized in materials with high conductivities and low thermal conductivities. A recently synthesized silicon allotrope of Si24 features highly anisotropic crystal structure nanometer-sized regular pores. Here, based on first-principles study without any empirical parameter we show that the slightly doped provide an order-of-magnitude...

We study the variations of electron–phonon coupling and their spectroscopic consequences in response to sliding two layers bilayer graphene using first-principles calculations a model Hamiltonian. Our shows that long wavelength optical phonon modes change sensitive unusual way depending on symmetry as well parity atomic structures that, accordingly, Raman- infrared-active behave differently upon direction size sliding. The renormalization by interlayer electronic is shown be crucial explain...

Quantum dots (QD) are regarded as ideal light emitters for current and next-generation displays. Hence, there is an urgent need to produce environmentally friendly QDs that show high efficiency and...

Abstract Quantum dot light emitting diodes (QD-LEDs) have high potential to be used in next-generation displays. The main challenge the commercialisation of QD-LEDs is improvement efficiency and stability blue QD-LEDs. most promising emitter for ZnTeSe QD, however it concerned that tellurium causes spectral broadening drop. In this work, we demonstrate effect Te clusters on electronic structures QDs through first principle calculation. photo dynamics at ensemble single level show lifting...

We study the variations of electron-phonon coupling and their spectroscopic consequences in response to sliding two layers bilayer graphene using first-principles calculations a model Hamiltonian. Our shows that long wave-length optical phonon modes change sensitive unusual way depending on symmetry as well parity atomic structures that, accordingly, Raman- infrared-active behave differently upon direction size sliding. The renormalization by interlayer electronic is shown be crucial explain...