A new superhard carbon allotrope oC48 is uncovered. The mechanical and electronic properties of oC48 were studied by using first principles calculations. The calculated results of elastic constants and phonon dispersion show that oC48 is mechanically and dynamically stable. The hardness of oC48 is predicted to be 73.3 GPa, which indicates the superhardness of oC48. The elastic anisotropy of oC48 were

The elastic properties of Cu − Al − Mn alloys with compositions along the Cu3Al → Cu2AlMn line and bcc-based structures, are studied by means of first-principles calculations. From the calculated elastic constants, the Zener's anisotropy, sound velocities and Debye temperature are determined. The theoretical results compare well with the available experimental data. The influence of vibrations is introduced

The tetragonal SrFeO2.84 single crystal was grown by using floating zone method, and followed by resistivity and magnetization measurements with respect to temperature. Here, the magnetization data shows an antiferromagnetic ordering below 63 K, accompanied by the formation of the charge ordering. However, an anomalous insulator to metal transition occurs below 40 K in the basal plane of SrFeO2.84

The stabilities and phase evolutions of the binary Bi–S compounds are investigated by using synchrotron radiation X-ray diffraction in a diamond anvil cell in combination with laser heating technique. When it is heated to 1300 K at 32.6 GPa, Bi2S3 decomposes into element S and a new BiS phase, which can be quenched to ambient conditions. The present results verify that cubic BiS, with an unprecedented

The new organic–inorganic hybrid zero-dimensional bismuth-chloride based compound: (C3H6N3S2)3BiCl6, was synthesized by slow evaporation at room temperature. Single-crystal X-ray diffraction analysis indicates that the compound belongs to the triclinic crystal system with the centrosymmetric space group P-1. The asymmetric unit contains one octahedral geometry of [BiCl6]3- and three protonated cations

The stability and the mechanical properties of β type Ti1-xFex binary alloys were systematically studied by means of first-principles calculations based on the density functional theory. Our results have demonstrated that the Ti1-xFex alloys in our consideration are stabilized as β phase and the formation energy decrease with the increase of alloy element Fe content. It is found that the mechanical

Here, we synthesized monolayer MoS2 under atmospheric pressure by chemical vapor deposition (CVD) using a quartz tube with a large-diameter up to 100 mm. The morphology of MoS2 thin films along the airflow direction was initially observed by the optical microscope. Raman spectra and atomic force microscopy (AFM) were utilized to characterize the thickness of samples. Moreover, the optical properties

High-temperature Raman spectroscopic study of order-disorder transition in Pentaerythritol [C(CH2OH)4] is reported. The changes in the Raman spectra with increasing temperature have been followed up to ≈503 K. We observe several changes in the spectra including merging of modes, appearance of new modes and sudden change in the slope of the frequency vs temperature curve at ≈ 452 K. In addition, sudden

We have investigated the technologically relevant, yet unmapped effect of excess charge carriers on electronic structure and electric conductivity of phagraphene (PG) membranes within the framework of density functional theory and the pseudopotential approach. The charge of the reference unit cell then changes from zero to n = ±e, ±2e, and ±3e, with e the magnitude of elementary charge. Electronic

Transition metal dichalcogenides (TMDs) with layered structures possess excellent electrical and thermal transport properties. In this work, bulk VSe2 sample with layered structure was fabricated by a conventional solid-state reaction method followed with spark plasma sintering process. The microstructure as well as thermoelectric properties were systematically studied. Bulk VSe2 possesses high electrical

Performing the scattering matrix approach, we calculate the current noise cross correlation and the differential conductance in the Majorana bound states (MBSs) comb. The teeth on the comb consist of topological super-conducting nanowire sandwiched between two quantum dots (QDs). We find that the nonlocal property of MBSs comb can be effectively modulated by the quantum dots. For only one “QD-MBSs-QD”

Lindemann developed the melting temperature theory over 100 years ago, known as the Lindemann criterion. Its main assumption is that melting occurs when the root-mean-square vibration amplitude of ions and atoms in crystals exceeds a critical fraction, η of the inter-atomic spacing in crystals. The Lindemann coefficient η is undefined and scientific papers report different η values for different elements

Bismuth molybdate low-temperature γ-phase (γ-Bi2MoO6) has been widely studied as catalytic compound, and a recent experimental study demonstrated that Ruthenium (Ru) doping on γ-Bi2MoO6 enhanced their CO to CO2 conversion capacity at low temperature. To elucidate the effect of Ru-doping on γ-Bi2MoO6 electronic properties, in the present work are calculated the electronic structure and optical properties

We report high-pressure neutron diffraction, and Raman spectroscopy data from the α- (Pnma) to β- (P63/mmc) phase transition in BaD2. The transition was observed at 2.53(5) GPa on pressure increase, and 1.65(5) GPa on pressure decrease, with a relatively narrow 0.20(5) GPa region of phase coexistence. We report the isothermal equations of state for the α-phase at 300 K and the β-phase at both 300 K

We report on measurements of critical current densities Jc and flux creep rates S of freestanding Ca(Fe1−xCox)2As2 (x ≈ 0.033) single crystals with Tc ≈ 15.7 K by performing magnetization measurements. The magnetic field dependences of Jc at low temperature display features related to strong pinning. In addition, we find that the system displays small flux creep rates. The characteristic glassy exponent

Recently the point defect responsible for the emission of cobalt in doped zinc oxide (ZnO) samples has been identified [24]. In this work we extend our investigation to other point defects in Co-doped ZnO. We use density-functional theory and GW calculations to obtain the orbital-resolved band structure of cobalt doped ZnO. We show that mainly O-p and Co-d orbitals take part in the process and confirm

We report on the effect of carbon ion-implantation on the critical behavior of Fe93Zr7 amorphous films. Both the as-grown and carbon-implanted Fe93Zr7 samples exhibit a second order ferromagnetic to paramagnetic transition. The critical exponents were investigated through different techniques such as modified-Arrott plot, the critical isotherm analysis and the Windom scaling relation. Analysis of the

An experimental report showed that Pt-decoration significantly increased the ZnO nanostructure sensitivity toward carbon monoxide (CO) gas. We performed DFT calculations to reveal the origin of this phenomenon. The Pt atom catalyzes the air O2 dissociation, which can interact with CO gas to form CO2 gas. This affects electronic resistance and leads to production of an electrical signal. These issues

We systematically study the geometric stability and hydrogen storage capacity of Ni atom decorated GaN monolayer (GaN-ML) with three types defects (VN, VGa and SW defect) using the first-principles calculations based on density functional theory (DFT-D2 method). For Ni-decorated defective GaN-ML, Ni atom can be stably combined on substrates due to higher binding energy, and the Ni atom can accommodate

The temperature dependent polarization properties along the c-axis of 1T-TaS2 single crystals are investigated. The dielectric constant in MHz region enhances with cooling from 150 K down to 12 K, whereas the spectra disperse only slightly. The dielectric loss spectra at various temperatures indicate a hopping process of localized carriers induced by the out-of-plane stacking disorder. We propose that

Introducing spin-polarized carriers in semiconductor lasers reveals an alternative path to realize room-temperature spintronic applications, beyond the usual magnetoresistive effects. Through carrier recombination, the angular momentum of the spin-polarized carriers is transferred to photons, thus leading to the circularly polarized emitted light. The intuition for the operation of such spin-lasers

The pressure-induced structural properties, anisotropic elasticity, ideal tensile and shear strengths of CuInS2 and CuInSe2 with ternary chalcopyrite structure are investigated by performing ab initio calculations. Single-crystal elastic constants, polycrystalline bulk modulus, shear modulus, Young's modulus, Poisson's ratio, the brittle/ductile characteristics and elastic wave velocities over different

We present phenomenological models calculations for the magnetic susceptibility, valence of Ce ions and the effective Bhor magneton number of Ce ion in CeCoSi system. We found that the susceptibility of this compound explained by the interconfiguration fluctuation (ICF) model. We obtain the valence of Ce ions 3.42 at the room temperature. This result suggests that CeCoSi system is a valence fluctuation

Density functional theory (DFT) calculation was carried out to understand the nature of the interactions between Cellulose/single-wall boron nitride nanotube (Ce/SWBNNTs), Fullerene (Ce/C60), and boron nitride nanosheet (Ce/BNNS) as a delivery system. There are very interesting results. So, the electronic properties are affected and altered. SWBNNTs is very sensitive to the Ce due to it has a higher

A new salt containing both dipolar and octupolar molecules has been synthesized and its structural features fully revealed, namely, its noncentrosymmetry. The microscopic optical properties of a neutral cluster were calculated probing several functionals; a better performance was observed for functionals with high percentage of Hartree-Fock exchange. The vector and septor irreducible components, for

We study the quantum disordered phase of the anisotropic Heisenberg spin one model with ferromagnetic nearest-neighbor interactions, frustrating antiferromagnetic next-nearest-neighbor interactions along the chain and antiferromagnetic interchain couplings along the axes perpendicular to the chain. We use the SU(3) Schwinger boson technique and calculate the phase diagram at zero temperature. The gap

In this paper, we study the magnetic properties of a diluted core-shell borophene structure. The system is composed by the mixed spins σ = ±1, 0 (in the core) and S = ±3/2, ±1/2 (in the shell). Indeed, the originality of this work is to introduce the non-magnetic atoms in the shell part of the borophene monolayer system and study their effects on the magnetic properties behavior. Firstly, the ground

Light illumination is widely used to tune the electronic properties of semiconductors. We have studied the effect of temperature and wavelength of light on the photoconductivity and persistent photocurrent (PPC) on an insulating (3 unit cells (u.c.) of LaVO3 (LVO) on SrTiO3 (STO)) and a conducting (5 u.c. of LVO on STO) oxide interface. Photo induced insulator to metal transition has been observed

In this study, the AuxPt100-x (x = 90, 50, 10) model alloy system was modelled molecular dynamic (MD) simulation for different atomic concentration percentage of platinum (Pt). The potential energy function was used the Embedded Atom Method (EAM). The bond-type index method of Honeycutt–Andersen (HA) and cluster-type index methods (CTIM-1 and CTIM-2) was used to detect the crystal/amorphous-type polyhedrons

The aim of this work is to determine the collective excitations and decay rate of plasma oscillations in a gapped graphene-GaAs double-layer structure within random phase approximation without temperature effects. Firstly, we utilize long wavelength approximation expansions of polarization functions and Coulomb bare interactions to observe the analytical expressions for plasmon frequencies. These analytical

In this paper, the first-principles full-potential linearized augmented plane-wave method (FPLAPW) is implemented to investigate the structural, magnetic, and electronic properties of (001), (111) and (110) surfaces of zinc blende (ZB) structure of ScC. At the equilibrium lattice constant (5.121 Å), the half-metallicity preserved in the bulk ScC, is destroyed at both Sc(C)-terminated (001), Sc(C)-terminated

The optical anisotropy of zinc-blende type-II GaAsSb/GaAs quantum wells (QWs) with (110) crystal orientation was investigated by using the multiband effective-mass theory. The optical matrix element for the y′([11̄0])-polarization rapidly decreases with increasing in-plane wave vector. On the other hand, in the case of the x′([001])-polarization, the optical matrix element is nearly independent of

Oxygen ion diffusion determines the performance of materials in energy conversion, energy storage and catalysis. For nominally pure cerium oxide, experiments measure high activation enthalpies while calculations predict low activation enthalpies. Moreover, for doped oxides, e.g. doped ceria, experiments show a high activation enthalpy for both pure ceria and for high dopant fractions, leading to a

Structural and electronic properties of cubic Ba2MgWO6 materials doped with Mo, Ti, La, Nd, Eu, Er, and Lu have been investigated within the density functional theory. The findings presented in this work suggest possible strategies for band gap engineering in Ba2MgWO6 and predicts the effects of La and Ti doping, i.e., the formation of (Ba,La)2Mg(W,Ti)O6 solid solutions, on the electronic structure

In this study, the adsorption characteristics of various gas molecules (CO, CO2, HCN, NH3, NO2, O3 and SO2) on Hittorf's violet phosphorene have been investigated based on first-principles calculations. All gases under consideration could be adsorbed via mixed of between physisorption and chemisorption, which makes it suitable for reversible sensors. The adsorption of NO2, O3 and SO2 causes stronger

We conducted DFT calculations and molecular dynamics simulation to investigate the effect of small (less than 1%) concentrations of As-antisite (AsGa) defect to the GaAs bulk lattice. We found that the lattice does not expand nor contract at 0.39% and 0.78% defect concentrations but retains the equilibrium lattice parameter of the GaAs. This clarifies the experimental observations of a plateau-type

The suitability of empirical potential molecular statics (MS) simulations to provide an approximate structural description of 90° glide set partial dislocation cores in GaAs is analyzed. This is of interest for investigation of the properties of dislocated nanostructures, which are too large for density functional theory simulations. In the MS method the atomic positions are iteratively relaxed by

This article is about structural, electronic, optical and thermoelectric properties of metal halide double perovskites Cs2AgInX6 (X = F, Cl, Br, I). These properties are computed using the highly accurate full potential linearized augmented plane wave method based of density functional theory. To acquire suitable ground state lattice parameters, generalized gradient approximation has been used. The

In this report, the gate leakage mechanism for AlGaN/GaN high electron mobility transistors (HEMTs) is consistently analyzed by means of temperature-dependent reverse gate current–voltage characteristics in the temperature range of 60–320 K. The gate leakage current of the AlGaN/GaN HEMT is studied by adjusting the experimental data using Poole–Frenkel (PF), and Fowler–Nordheim (FN) tunneling. In the

Based on the first-principles calculations, we investigated the thermal expansion and related vibrational properties of monolayer α-Se and binary compounds α-TeSe2. The effect of binary compounds on thermal expansion properties is explored theoretically. We find the two monolayers show totally positive thermal expansion from 0 to 500 K. The linear thermal expansion coefficients are closed to each other

In this paper, recombination dynamics in GaAs1-xNx semiconductor alloy with a nitrogen content of 1.6% are investigated using Photoluminescence (PL) and Time-Resolved Photoluminescence (TRPL) Spectroscopy. At temperature below 80K, the TRPL measurements show the competition of two recombination processes with two different decay times. The localized to delocalized electron transition with slow decay

An analytic approach has been carried out to calculate the lattice resistance for movement of a straight dislocation in the crystal lattice at a velocity corresponding to common tensile test, which provides a different method from the classic Peierls-Nabarro (P–N) model. In the present model, movement of dislocation is supposed to consist of oscillation at equilibrium sites and instantaneous jumping

In this work, we investigate structural, optical and magnetic properties of Zn0·96V0·04O (ZnV4), Zn0·92V0.04Gd0.04O (ZnV4Gd4) and Zn0·88V0.04Gd0.08O (ZnV4Gd8) nanoparticles synthesized by sol–gel. In our protocol, the water has been slowly released following an esterification reaction, then, this solution was dried under supercritical conditions of ethyl alcohol and heat treatment in air at 500 °C

Raman scattering spectroscopy is powerful, express and non-destructive method for control of phase composition of different materials. To determine the crystalline part, one should know the ratio of Raman cross sections of crystalline to amorphous phases. In this Letter we report on accurate comparative measurements of the Raman scattering from monocrystalline and nanocrystalline Ge, as well as from

First-principles calculations were carried out to investigate the structural and mechanical stability for the both phases of Mo2N. The results show that the tetragonal β-Mo2N phase is more thermodynamically stable depending on their low enthalpy of formation, while the cubic γ-Mo2N phase is more mechanically stable depending on their mechanical properties. Furthermore, the electronic properties are

We investigate semi-analytically the coherent electronic transport properties of a bent, twisted, compacted or stretched simple cubic nanocrystal within the nearest neighbor tight-binding approach and Green’s function technique. We take the bent, twisted, compacted and stretched part of the nanocrystal as a center wire and the other ideal parts as two semi-infinite similar left and right leads. Also

Cadmium telluride (CdTe) is immensely interesting narrow band gap semiconductor with high electrical conductivity having promising applications in new-generation electronics and photo-electronic devices. In the present study, CdTe thin film was fabricated by thermal evaporation technique onto pre-cleaned glass substrate. The EDAX result indicates that the prepared thin film has non-stoichiometric nature

In this work, we have studied the entropy and specific heat of graphene as a function of temperature in the presence of an external magnetic field. In this regard, we have considered two regions of temperature such as low and high temperatures. Here, we have used a noncommutative phase-space to obtain electronic properties of graphene. The entropy is decreased with increasing the magnetic field for

In the present work the structural, electronic and optical properties of pure CaZrO3 have been tuned by the magnesium (Mg) doping concentrations (1.41%, 2.82% and 4.23%) by first-principles computation, based on the density functional theory (DFT), implemented within the CASTEP code with Perdew-Burke-Ernzerhof-Generalized-Gradient-Approximations (PBE-GGA) exchange correlation functional and USP (ultra-soft

This work presents theoretically investigate the electron transport through a PN junction in two-dimensional topological insulator transistor made by a HgTe/CdTe quantum well with inverted-band structure. We find distinct features of the transmission by considering the Rashba spin–orbit interaction (RSOI). It’s demonstrated that the transmission can be effectively tuned by changing the incidence angle

Compounds with 4d-transition-metal elements show a series of novel quantum states, such as spin liquid, correlated topological states, which maybe come from the spin-orbit interaction in 4d transition-metal. Here we explored the magneto-transport properties of rare-earth-element doped 4d-transition-metal oxide-K0.6RhO2 (RE-K0.6RhO2) crystals. Centimeter-sized Sm-, Dy-, Ho-doped (doping concentration

Calcite is the most important component of limestone, an essential building material. When adsorbing water, the strength of calcite decreases, resulting in safety problems. Density functional theory (DFT) is widely used to elucidate the adsorption mechanisms of calcite surface at a molecular level. The adsorption structures and energies of H2O on calcite (104) surface were studied systematically for

Electronic structures and magnetic properties for (Cr, X) (X = Ga, In) co-doped 4H silicon carbide (SiC) are studied by first-principles calculations. Our results show that all configuration of (Cr, X) (X = Ga, In) co-doped 4H–SiC are favor ferromagnetic state. The (Cr, Ga4) and (Cr, In4) configuration is the most stable one with ΔEFM of −224.9 meV and −269.6 meV, respectively. Based on the mean-field

We review theoretical and experimental results on geometric spin-phase detection and manipulation in mesoscopic Rashba spin-orbit (SO) rings. A one-dimensional (1D) model capable of providing physical insight into electronic spin dynamics and interferometry under SO and Zeeman fields is developed to discuss spin transport in Rashba rings. The model gives an accurate prediction of the Aharonov-Casher

We report the spin transport properties in a pigment-red (perylene-3,4,9,10-tetracarboxylic dianhydride: PTCDA) film prepared by thermal evaporation. In a palladium (Pd)/PTCDA/Ni80Fe20 tri-layer sample, a pure spin-current is generated in the PTCDA layer by using the spin-pumping driven by the ferromagnetic resonance of the Ni80Fe20 film. The generated spin current is absorbed into the Pd layer, converted

In this work, we show a line-shape analysis of the resonant Raman scattering spectrum of un-doped CdTe single crystal. We found that the main peak correspondent to the longitudinal-optic (LO) phonon mode is asymmetrically broadened toward the high-frequency side. We attributed this asymmetry to an electron-phonon coupling effect, which was demonstrated using a Fano-type function to describe the spectrum

A core/shell geometric structure is described by ferrimagnetic mixed spin square Blume-Capel Ising nanowire, using MMFM, i.e., molecular mean field method, or rather self-consistent field theory. In this model, antiferromagnetic forms are allowed to spin interactions, i.e. the nearest neighbors. We tested the influence of crystal and external magnetic fields on a ferrimagnetic mixed spin-1 and spin-5/2