$T$ graphene, a two-dimensional carbon allotrope with tetrarings, is investigated by first-principles calculations. We demonstrate that buckled graphene has Dirac-like fermions and high Fermi velocity similar to even though it nonequivalent bonds possesses no hexagonal honeycomb structure. New features of the linear dispersions are different from revealed. $\ensuremath{\pi}$ ${\ensuremath{\pi}}^{*}$ bands two comprising sublattices key factors for emergence fermions. its types nanoribbon...

Interfacial integration of a shape-engineered electrode with strongly bonded current collector is the key for minimizing both ionic and electronic resistance then developing high-power supercapacitors. Herein, we demonstrated construction micro-supercapacitors (VG-MSCs) based on high-density unidirectional arrays vertically aligned graphene (VG) nanosheets, derived from thermally decomposed SiC substrate. The as-grown VG showed standing basal plane orientation grown (0001̅) substrate,...

Double-layer graphene epitaxially grown on silicon carbide was used to Q-switch a Tm:YAG laser. Stable Q-switched laser pulses at the central wavelength of 2.01 μm were obtained. The maximum average output power, pulse repetition rate, and single energy 38 mW, 27.9 kHz, 1.74 μJ, respectively. Our results illustrate that can be as saturable absorber 2 region.

Intrinsic diamagnetism of graphene is studied both theoretically and experimentally, to unravel the magnetic response chiral massless fermions. Comprehensive formulas predicting variation magnetization with field temperature are developed. Graphene $M$ at low temperatures particularly large $M\ensuremath{\propto}\ensuremath{-}\sqrt{B}$, intrinsically different from normal materials. The quantum Berry phase $\ensuremath{\pi}$ linear energy dispersion responsible for this intriguing...

The magnetism of graphene has remained divergent and controversial due to absence reliable experimental results. Here we show the intrinsic edge states revealed based on unidirectional aligned sheets derived from completely carbonized SiC crystals. It is found that ferromagnetism, antiferromagnetism diamagnetism along with a probable superconductivity exist in irregular zigzag edges. A phase diagram constructed evolution magnetism. ferromagnetic ordering curie-temperature fundamental...

Temperature-dependent Raman scattering is performed on unsupported vertical graphene sheets, which are approximate to free without supporting the substrate. Here observed G peak line shift with temperature completely consistent theoretical prediction based first-principles calculation graphene, and our result helpful understand intrinsic anharmonic phonon characteristics of divergence temperature. However, linewidth variation different from prediction. To reveal origins, a simplified Klemens...

Graphene covered SiC powder (GCSP) has been fabricated by well established method of high temperature thermal decomposition SiC. The structural and photocatalystic characteristics the prepared GCSP were investigated compared with that pristine powder. Under UV illumination, more than 100% enhancement in activity is achieved degradation Rhodamine B (Rh B) catalyst possible mechanisms underlining observed results are discussed. suggested as a composite graphene based material great potential...

We have prepared Ca-intercalated multilayer epitaxial graphene films on silicon carbide and observed superconductivity in them with both magnetic transport measurements. Superconducting transition has been detected at temperature up to 7 K the thickness down 10 layers grown Si-face C-face of carbide. The result demonstrates intercalated as a good platform study graphene-based superconductivity.

Tantalum arsenide is experimentally verified as a Weyl semimetal recently. However, it difficult to grow large TaAs single crystals due the decomposition prior reaching its melting point. Here we report an improved chemical vapor transport method using iodine agent get large-size, high-quality up 1 cm. X-ray diffraction confirmed that they are tetragonal TaAs. Specific heat of was measured from 2 K room temperature, and hence entropy enthalpy were obtained, which helpful in designing optimal...

Abstract Due to the presence of core effects high‐entropy materials, it is believed that impact carbon vacancy in carbides may differ from transition metal monocarbides. In this work, nonstoichiometric (Ti 0.2 Zr Hf Nb Ta )C 1− x (HEC ) with variable concentration were fabricated by spark plasma sintering using powder mixtures carbide and metallic powders. Compared corresponding monocarbides, decline rates lattice constant elastic modulus obviously slower as increased, indicating a more...

Bipolar carrier transfer channels exist in the situ epitaxial-graphene-wrapped 6H-SiC core–shell heterojunction due to self-doping of graphene. Due special interface structure and high graphene quality, this material exhibits significant photocatalytic enhancement. Its hydrogen evolution efficiency is greater than that Pt/SiC composite. This micrometer-sized metal-free photocatalyst an activity comparable metal-based nanophotocatalysts. As a service our authors readers, journal provides...

Abstract By means of density functional theory and experiments, surface chemical reactivity single crystals NbAs TaAs Weyl semimetals is studied. exhibit outstanding toward simple molecules (oxygen, carbon monoxide, water), with several active sites available for reactions (adsorption, decomposition, formation reaction products, recombination decomposition fragments). When different species are adsorbed on semimetals, strong lateral interactions between coadsorbed occur, evidenced by...

Video compression standard H.264/AVC was released in 2003, and has been dominating the industry for past decade. Over last few years, a number of next-generation standards/formats like VP9 (2012), H.265/HEVC (2013) AV1 (2018) were introduced, all claiming significant improvement over H.264/AVC. In this paper, we present our evaluation performance these standards. Our is conducted using open-source encoder implementations standards, x264 (for H.264/AVC), x265 H.265/HEVC), libvpx VP9) aomenc...

A fiber laser resonantly pumped 1.645 μm passively Q-switched Er:YAG is reported. Graphene on a silicon carbide was used as the saturable absorber for Q-switching. The pulse energy of 7.05 μJ, with repetition rate 35.6 kHz and an average output power 251 mW.

Materials with low thermal conductivity, which can minimize heat dissipation, play a central role in many practical applications, such as thermoelectric devices and barrier coatings. We report the synthesis conductivities of narrow band gap semiconductors NaSnAs NaSnP, measured minimum lattice are 0.62 0.58 W/m/K. The values close to calculated 0.46 0.40 W/m/K, respectively, obviously lower than that for their closely related compound $\mathrm{NaS}{\mathrm{n}}_{2}\mathrm{A}{\mathrm{s}}_{2}$,...

TaTe2 is a quasi-2D charge density wave (CDW) compound with distorted-1T–type structure exhibiting double-zigzag chains. Here we report the Fermi surface topology of low-temperature phase (LT-TaTe2) by anisotropic magneto-transport and magnetic measurements on high-quality single crystals. An anomalous large linear magnetoresistance up to 140% at 3 K in 9 T was observed, suggesting existence small pocket Dirac cone state quantum transport models. Moreover, strong anisotropy observed for...

Denoising module is required by any practical video processing systems. Most existing denoising schemes are spatio-temporal filters which operate on data over three dimensions. However, to limit the number of inputs, these only utilize one reference frame and cannot fully exploit temporal correlation. In this paper, a recursive filter named multihypothesis motion compensated (MHMCF) proposed. To correlation, MHMCF performs estimation in frames construct multiple hypotheses (temporal...

With the prevalence of high speed Internet access, emerging video applications such as remote desktop sharing, virtual infrastructure, and wireless display require compression efficiency screen contents. However, traditional intra inter coding tools were designed primarily for natural Screen contents have significantly different characteristics compared with nature contents, e.g. sharp edges, less or no noise, which makes those sufficient. In this research, a new color palette based tool is...

A simple optical-electronic device that possesses widescale adjustability in its performance is specially required for realizing multifunctional applications as optical communication and weak signal detectors. Here, we demonstrate an epitaxial graphene (EG)/n-type SiC Schottky ultraviolet (UV) photodiode with extremely responsivity response speed. It found the speed of can be modulated over seven orders magnitude from tens nanoseconds to milliseconds by changing working bias 0 −5 V, while...

By means of high-resolution electron energy loss spectroscopy, we investigate the low-energy excitation spectrum transition-metal monopnictides hosting Weyl fermions. We observe gapped plasmonic modes in (001)-oriented surfaces single crystals NbAs and TaAs at 66 68 meV, respectively. Our findings are consistent with theory estimate an effective Coulomb interaction strength ${\ensuremath{\alpha}}_{\mathrm{eff}}\ensuremath{\approx}0.41$ for both samples. also demonstrate that modification...

We report a new type of MAX phase (M=transition metals, A=main group elements, and X=C/N), Nb3 As2 C, designated as 321 phase. It differs from all the previous Mn+1 AXn phases in that it consists an alternate stacking one MX layer two MA layers its unit cell, while only is allowed usual phases. The exhibits bulk modulus C up to 225(3) GPa determined by high-pressure synchrotron X-ray diffraction, highest values among Isostructural V3 P2 Ta3 are also found exist. First-principles calculations...

Structure and photocatalytic activity of high quality graphene covered SiC powder (GCSP) composites as metal-free photocatalysts with different sizes layer numbers are investigated. The results indicate that the GCSP 4–9 layers reveal outstanding enhancement among other numbers. Moreover, it is found smaller particles have higher than larger ones more 730% improvement achieved by derived from 0.5 μm relative to pristine powder, which 6 times photoreduced oxide/SiC composite. Our demonstrate...

We present a new methodology that allows for more objective comparison of video codecs, using the recently published Dynamic Optimizer framework. show how this is relevant primarily to non-real time encoding adaptive streaming applications and can be applied any existing future codecs. By VMAF, Netflix's open-source perceptual quality metric, in dynamic optimizer, we offer possibility do visual optimization codec thus produce optimal results terms PSNR VMAF. focus our testing full-length...