We consider the excitonic effects on the thermal properties in the AB-stacked bilayer graphene. The calculations are based on the bilayer generalization of the usual Hubbard model at the half-filling. The full interaction bandwidth is used without any low-energy assumption. We obtain the unusually high values for the electronic figure of merit even at the room-temperatures which is very promising for

In this paper, we propose a method to calculate the exact Taylor series of the scattering matrix in general multiterminal tight-binding systems to arbitrary order N, which allows us to find the Taylor expansion of Landauer conductance in mesoscopic systems. The method is based on the recursive scattering matrix method (RSMM) that permits us to find the scattering matrix of a system from the scattering

In this study, density functional theory (DFT) has been used to build armchair graphene nanoribbon (AGNR) gas sensor and study its capacity to detect carbon monoxide (CO), carbon dioxide (CO2), and sulfur dioxide (SO2) gases. The adsorption of these gases on AGNR was confirmed based on the adsorption energy (Eads), adsorption distance (D), charge transfer (ΔQ), density of states (DOS), and band structure

It is essential to detect the characteristic gas products of SF6 decomposition for fault diagnosis of gas-insulated switchgear (GIS). The model of Rh doped MoS2 was built by Materials Studio software. The micro process of three SF6 partial dissociation products (SO2, SOF2, SO2F2) approaching the Rh–MoS2 surface and reaching a stable state was simulated. The modification effect of Rh doped MoS2 was

We conducted extensive density functional theory calculations within GGA + U approach to explore the geometry, electronic structure and optical properties of armchair and zigzag zinc oxide nanoribbons as a function of width. Our results show that single layered armchair ZnONRs are semiconductors, whereas the zigzag counterparts are metallic. However, the electronic energy gap in armchair configurations

Two-dimensional (2D) quantum spin Hall (QSH) insulator are promising candidates for miniaturized electronic and dissipationless transport devices. The bottleneck preventing applications from QSH phase, however, is lack of feasible 2D materials in experiments so far. By using first-principles calculations, here we propose a realistic 2D QSH phase in tetragonal CuN, which is dynamically and mechanically

Strain in the lattice has a profound effect on the electrical and optoelectronic properties of the material. Here we demonstrate the extent effect of micro-strain applied to graphene, induced by silver nanowires (AgNWs), on its lattice and electronic properties. In the typical process, we found that the micro-strain effect has critically expanded the lattice carbon-carbon bond length as a dramatic

We model the electron transport current as the photon energy is swept through several resonances of a multi-level quantum dot, embedded in a short quantum wire, coupled to photon cavity. We use a Markovian quantum master equation appropriate for the long-time evolution and include the electron–electron and both the para-and the diamagnetic electron–photon interactions via diagonalization in a truncated

Using the tight-binding BHZ model and Landauer-Büttiker formalism, the topological invariant of the finite width of ribbons of HgTe/CdTe quantum well is studied in the absence and presence of an external transverse electric field. It will be recognized that a critical current changes topological invariant of ribbons of quantum well. This topological phase transition, which occurred by adjustment of

A transfer matrix approach is used to study the electronic transport in graphene superlattices with long-range correlated barrier spacements. By considering the low-energy electronic excitations as massless Dirac fermions, we compute by transmission spectra of graphene superlattices with potential barriers having spacements randomly distributed with long-range correlations governed by a power-law spectral

The thin-film of hierarchical rutile/anatase TiO2 nanorod/nanoleafs on fluorine-doped tin oxide glass was prepared via a facile method. For this purpose, the hydrothermal method was used for the synthesis of rutile-phase nanorods on the TiO2 seeded FTO, and aqueous chemistry was applied for growing anatase-phase nanoleafs on the nanorods. The structural, morphological, and optical properties of coating

In this paper, an insulator-semiconductor-insulator plasmonic waveguide is proposed based on InSb in the terahertz range. The proposed plasmonic waveguide is an integrated temperature and refractive index sensor. The plasmon-induced transparency used in this integrated sensor reduces the sensor bandwidth by coupling two rolled-up micro-tubes. The sensitivity of the proposed sensor for temperature and

The (1-x) (Al0·2La0·8TiO3) + (x) (BiFeO3) nanocomposites were synthesized via low temperature hydrothermal method. The X-ray diffraction (XRD) patterns established the tetragonal phases for x = 0.2 while the cubic phases were detected in case of x = 0.4, 0.6 & 0.8 composites. The surface morphology was analysed using field emission scanning electron microscope (FESEM) and transmission electron microscope

The importance of interband transitions on the ultrafast relaxation process in photoexcited pristine graphene is evaluated by means of an ensemble Monte Carlo simulator. Impact ionization and Auger recombination in the collinear limit are considered, together with phonon-induced generation and recombination and intraband scattering mechanisms. The results show that collinear impact ionization is dominant

In this work, a flexible photodetector has been fabricated based on graphene/CdS quantum dots hybrid structures. Large area graphene film has been synthesized by chemical vapor deposited technique. After transferring it onto polyethylene terephthalate (PET) substrate, the sandwiched film of PET/graphene/PET showed high transparency. Also, using a chemical bath deposition method, a hybrid film of graphene/CdS

In this paper, structural and electronic properties of CrI3 magnetic nanotubes (NTs) are studied using density functional theory. Both armchair and zigzag CrI3 nanotubes demonstrate a high correlation in strain energy between each other independently on accounting the Hubbard correction. The strain energies decrease with expansion of the tube diameter making the tubes’ synthesis with a diameter larger

We investigate the electromechanical and magnetic response of normal-zigzag phosphorene nanoribbons (nZPNRs) to the Dresselhaus spin-orbit coupling (SOC) and Rashba SOC, electric fields, exchange fields, and uniaxial strains. It is found that, when the typical exchange fields, developed by combining a ferromagnetic (FM) state with one of the antiferromagnetic (AFM) states, are applied to the system

The investigations of quantum spin Hall effect and the edge states manipulation of two dimensional topological insulators are very salient for the practical applications and fundamental sciences. The high thermoelectric efficiency of these materials has also been confirmed, recently. So, in this study the first-principles calculations are implemented based on density functional theory in the presence

Spin-polarized density-functional theory calculations with generalized gradient approximation (GGA) as the exchange-correlation functional have been performed to study the energetics, electronic and magnetic properties of the monolayer WSe2 doped with atomic impurity atoms. We have considered selenium (Se) substitution by pnictogens (N, P, As, Sb and Bi) or halogens (F, Cl, Br, I and At). We also investigate

The optical properties of a spherical topological insulator embedded concentrically in a single-electron system consisting of a core–shell GaAs quantum dot are analyzed, when the system is under a uniform external magnetic field. The topological insulator’s magnetoelectric response is computed in the effective framework of θ-electrodynamics, which allows analytical calculations for the induced electric

In this study, the mechanical properties of Si/Ge multilayer nanofilms were simulated by molecular dynamics (MD) in tensile and compression tests. The tensile test results show the fracture mechanism of the Si/Ge multilayer nanofilm. The phase transition process of the Si/Ge multilayer films is revealed by the strain energy distribution and structure distribution during the tensile test. The mechanical

Electronic spectra of AA- and AB- graphene bilayers have been investigated for the case when P-symmetry is broken both inside and between the layers. We have focused special attention on the new regime when the band gaps in different layers have opposite signs. For example, the spectrum of AB bilayer is gapless in the case when band gaps of monolayers are equal in magnitude and opposite in sign. At

First-principles density functional theory calculations are performed to study the effects of local shear strain on the structural, mechanical and electronic properties of zigzag graphene nanoribbon with a topological line defect (LD-ZGNR). By changing the nanoribbon width N (N is the number of zigzag chains in the left or right ribbons of the topological line defect) and deformation positions, the

The modifications in structural and optical properties of metal organic vapour phase epitaxy (MOVPE) grown stacked layers of InSb/GaSb nanostructures which were investigated as a function of the InSb quantum dot (QD) layer deposition time using scanning probe microscopy (SPM), transmission electron microscopy (TEM), photoluminescence (PL) and Raman spectroscopy have been reported in this work. At 10 K

Spin polarization and half metallicity are the basic properties of spin electronics devices. The electronic and magnetic characteristics of the CuHg2Ti-kind structure Zr2VIn full Heusler alloy in the bulk and (111), (001) and (110) surfaces are explored using the first-principles investigation based on the density functional theory. The results show that the bulk Zr2VIn alloy achieves a ferromagnetic

We have applied wave packet formalism to investigate the dynamics of electron transport in semiconductor nanodevices shaped in branched nanowires. The nanowires are formed by quantum channels with a width of 10 nm, in which a two-dimensional electron gas is scattered. The theoretical model is based on the numerical solution of the time-dependent Schrödinger equation, within the effective-mass and envelope

The properties of multi-walled MoS2 nanotubes have been investigated by the first principles calculations and by molecular mechanics (MM) simulations using a revised three-body force field. The density functional theory (DFT) calculations have been performed on single-, double- and triple-walled MoS2 nanotubes. The new version of the force field is able to reproduce the structure integrity of the MoS2

The binding energy of a donor impurity in a wurtzite GaN/AlxGa1-xN core-shell nanowire is investigated by a variational method combined with a finite-difference algorithm. A semi-empirical formula is derived to express the temperature dependence of static dielectric constants for wurtzite structure. The temperature influence on impurity binding energy is actually not very prominent when considering

In the present work, the electronic transport properties of biberyllocene and bimagnesocene has been investigated and the influence of bridge sulfur atom between molecule and electrode on the electronic transport properties has also been explored. The most stable structures of biberyllocene and bimagnesocene with sulfur or not have been obtained through geometry optimization. Then, the equilibrium

In this study, the stability and thermoelectric properties of MgO (111) and (100) monolayers under compressive and tensile strain were investigated by density functional theory. The flat MgO (111) revealed to be stable against a biaxial and uniaxial tensile strain of up to ε = 15% and compressive strain of up to ε = −2% for biaxial strain and −5% for uniaxial strain. The rumbled MgO (100) showed stability

Two-dimensional (2D) materials design for nanoscience and nanotechnology has attracted continuously the researchers' attention because of the important role in the next generation of optoelectronics. In this paper, we report results concerning the prediction of a new 2D material, Lithium Chloride LiCl, using first-principles calculations. This material is proposed for the detection and absorption of

Graphene-based micro-tubes (μ-GTs) with good tubular structure were successfully fabricated from commercial graphene oxide dispersion by the electrospray deposition technique and thermal reduction. As a result of the structural changes, the electrical conductivity of the μ-GTs clearly increased as the annealing temperature increased. In particular, the μ-GTs with lower annealing temperatures exhibited

Within the spin polarized density functional theory formalism, the properties (structural, magnetic, electronic and optical) of transition metal (TM) substitutional doping as well as adsorption on monolayer TcS2 has been investigated. The TMs considered in this study were Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn. TM substitutional doping was found to be energetically favored under S-rich conditions

Silver nanoparticles AgNPs having small (6–8 nm) diameter, were synthesized in water in solutions and left interacting with diluted 3d metals (Co2+ or Ni2+ ions) solution (1–5 ppm range). The interactions between AgNPs and the metallic ions modify the optical response of the nanoparticles demonstrating their ability to capture metallic ions from water and making them valuable as metal contamination

In this work we investigate theoretically the influence of a Fermi velocity modulation in the electronic and transport properties of magnetic graphene superlattices. We solve the effective Dirac equation for graphene with a position dependent vector potential and Fermi velocity and use the transfer matrix method to obtain the transmission coefficient for the finite cases and the dispersion relation

Based on the first principle calculation, Pd-doped MoS2 (Pd–MoS2) monolayer has been proposed to adsorb the main decomposition products of SF6: SOF2 and SO2F2. Pd–MoS2 monolayer, SF6 adsorbed Pd–MoS2 monolayer, SOF2 and SO2F2 adsorbed Pd–MoS2 monolayer are built and optimized to obtain the most stable structures. In order to meet to the actual situation, both of single and double gas molecules adsorption

Highly luminescent Ag doped ZnO nanocrystals were synthesized in controlled manner by wet chemical route at room temperature and effects of Ag doping and three different ligands polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA) and biotin (BT) attached were investigated. The phase purity, crystallinity and crystallite sizes of as prepared nanoparticles (NPs) were characterized by X-ray diffraction

In this paper, the mechanical properties of multilayer graphene embedded in aluminum matrix ([email protected]) under uniaxial tension were investigated using molecular dynamics (MD) simulation method. The results clearly show that the graphene layer could provide effective barriers against the dislocation propagation across the interfaces resulting in the outstanding increment of the composite stiffness

This paper presents an investigation on the out-of-plane behaviour of graphene when cyclically loaded in-plane. Using an atomistic finite element approach, previous developed and validated by the authors, the stress-strain behaviour of graphene is evaluated under different cyclic loading tests (uniaxial, biaxial, shear). To simulate the bonds between carbon-carbon (C–C) atoms, beam elements are used

In this paper, we investigated the possible formation of polarons and bipolarons in graphene under a laser field. The LLP framework is used to solve the stated problem. We see that the laser greatly affects the properties of the polaron in graphene. We show that the laser also increases the first energy level of the polaron in the structure. It is shown that the laser can be used to modulate the band

In this study, the electronic band structures of hybrid graphene/nitrogene/graphene hetero-trilayers (Grap/N/Grap HTLs) are investigated by using the first-principles calculation. This calculation reveals that both the nitrogene and graphene in the Grap/N/Grap HTL can preserve their intrinsic electronic properties via van der Waals interactions, which are stronger than those between graphene and phosphorene

By considering quantum impurities in the superconductors, we mimic their influences on the phase transition in a Josephson junction. It is found that the impurities in the superconductors can take nontrivial effects to the Josephson phase transition, and they are able to promote or hinder the 0→π phase-transition phenomenon. Namely, for the 0 (π) junction with one impurity, it has an opportunity to

Building eco-friendly thermoelectric materials has always been one of the most important goals to protect the environment. Recently, a new carbon allotrope called “twin graphene” is proposed, which has outstanding electronic and mechanical performance. Based on the non-equilibrium Green's function, we investigate the thermoelectric properties of armchair and zigzag twin graphene nanoribbons and the

An analysis of the strain-induced group velocity (GV) and effective mass (EM) of massless topological Dirac fermions on the SnTe (001) surface, protected by crystalline symmetry, is presented. Using the traditional semi-classical k→⋅p→ approach by associating fermions with wave-packets, we find that the expression for the energy dispersion surface as well as both GV and EM are anisotropic in the absence

Gallium oxide (Ga2O3) nanostructures (NSs) are grown on Si substrate via vapor-solid (VS) mechanism by the carbon-hydrogen reduction of gallium oxide powder in chemical vapor deposition (CVD) system. The NSs are synthesized at different deposition temperatures of 850–1150 °C with the apparent activation energy of 120.98 kJ/mol(1.24 eV/atom). The crystalline monoclinic phase is confirmed by high-resolution

Graphene, a new smart material, has attracted remarkable attention in recent years owing to its tunable band structure and strong light-matter interaction. Compared to typical absorber, graphene absorber is recently considered as a highly promising candidate for multi-mode purpose. Here, a new tunable hexagonal-shape graphene-based THz absorber is proposed. To achieve nearly perfect broadband terahertz

Current–voltage characteristics of a spintromechanical device, in which spin-polarized electrons tunnel between magnetic leads with anti-parallel magnetization through a single level movable quantum dot, are calculated. New exchange- and electromechanical coupling-induced (spin-polaronic) effects that determine strongly nonlinear current–voltage characteristics were found. In the low-voltage regime

Motivated by some earlier experimental observations on the magneto-optical absorption and cyclotron resonance in graphene, we carry out systematically a theoretical investigation of the magneto-optical absorption in graphene monolayer situated on a substrate. The effect of electron–impurity scattering is considered at low temperatures. The magneto-optical absorption coefficient (AC) is calculated using

By using first principle method, the van der Waals (vdW) heterostructure has been extensively studied as anode material. We demonstrate that silicene/BN vdW heterostructure has a lower diffusion barrier, good Na-ion mobility, enhanced mechanical stability compared with pristine silicene system from the synergy effect between BN and silicene. And at the same time, acceptable high storage capacity can

Previously, the PtSe2 has been proved to absorb light in the infrared band, but most of devices based on PtSe2 were reported in visible light applications while few of them applied in near-infrared. In the visible band, the silicon may absorb most of the light wave, and the device does not make full use of the absorption characteristics of the PtSe2. In our work, we form heterojunction by growing PtSe2

The magnetization loops of a hexagonal spin-3/2 Ising nanotube are examined in the framework of the effective field theory with correlations, based on the differential operator technique. We have explored the impacts of distinctive exchange couplings on key physical parameters such as Phase diagram, magnetization, susceptibility, internal energy, and specific heat. Some special phenomena are inspected