Zinc-blende Structure Research Articles

Hydration and mechanical properties of arabinoxylan, (1,3;1,4)-β-glucan, and cellulose multilayer films simulating the cell wall of wheat endosperm

The cell walls of wheat endosperm, which play a pivotal role in seed germination, exhibit a laminated structure primarily composed of polysaccharides. In this study, composite multilayer films were prepared using arabinoxylan (AX), (1,3;1,4)-β-D-glucan (MLG), and cellulose nanofibers (CNFs), and the effect of polymer blend structure on cell wall hydration and mechanical properties was investigated. Atomic force microscopy and X-ray diffraction indicated that the network structure of MLG/CNF exhibits a higher degree of continuity and uniformity compared to that of AX/CNF. Mechanically, the extensive linkages between MLG and CNFs chains enhance the mechanical properties of the films. Moreover, water diffusion experiments and TD-NMR analysis revealed that water molecules diffuse faster in the network structure formed by AX. We propose a structural model of the endosperm cell wall, in which the CNFs polymer blend coated with MLG serves as the framework, and the AX network fills the gaps between them, providing diffusion channels for water molecules.

Eu3+ singly-doped and Eu3+/Sm3+ co-doped ZnS quantum dots: structure, optical properties and energy transfer.

In this study, Eu3+ ion singly doped and Eu3+/Sm3+ ions co-doped ZnS semiconductor quantum dots (QDs) were successfully synthesized using a wet chemical method in 1-octadecene (ODE) solvent. The successful doping of Sm3+ and Eu3+ ions into the ZnS host lattice and the composition and valence of the elements present in the sample were confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Structural and morphological studies revealed the presence of Eu3+-doped ZnS and Eu3+/Sm3+ co-doped ZnS QDs of about 3-4 nm size with a zinc blende structure. The Judd-Ofelt (J-O) intensity parameters of Eu3+-doped ZnS QDs were determined from their fluorescence spectra. The optical properties of Eu3+/Sm3+ co-doped ZnS QDs were studied by changing the Eu3+ ion concentration and fixing the Sm3+ ion concentration. The photoluminescence (PL) spectra of Eu3+/Sm3+ co-doped ZnS QDs were obtained at an excitation wavelength of 403 nm (6H5/2 → 6P3/2 transition of Sm3+ ions) in the 525-725 nm range. The effective energy transfer (ET) process from Sm3+ to Eu3+ ions was confirmed and explained in detail using the Reisfeld approximation and the Inokuti-Hirayama model. The CIE color coordinates of the Eu3+/Sm3+ co-doped ZnS QDs were obtained using PL spectral data. Eu3+/Sm3+ co-doped ZnS QDs exhibited a long lifetime and emitted warm red light. These interesting properties give Eu3+/Sm3+ co-doped ZnS QDs great potential for applications in photovoltaics, photocatalysis, and biomarkers.

The shift current photovoltaic effect response in wurtzite and zinc blende semiconductors via first-principles calculations.

Recently, the search for materials with high photoelectric conversion efficiency has emerged as a significant research hotspot. Unlike p-n junctions, the bulk photovoltaic effect (BPVE) can also materialize within pure crystals. Here, we propose wurtzite and zinc blende semiconductors without inversion symmetry (AgI, GaAs, CdSe, CdTe, SiGe, ZnSe, and ZnTe) as candidates for achieving the BPVE and investigate the factors that affect the shift current. GaAs with a wurtzite structure exhibits the highest shift current value of 31.8 μA V-2 when spin-orbit coupling is considered. Meanwhile, the peak position of the maximum linear optical conductivity and shift current in the wurtzite structure is lower than that in the zinc blende structure. In addition, we also found that strong covalency within the same main axis group element significantly influences the shift current, exemplified by wurtzite SiGe, which exhibits 15.8 μA V-2. Our research highlights the importance of a smaller band gap, reduced carrier effective mass, and increased covalency in achieving a substantial shift current response. Ultimately, this study provides valuable insights into the interplay of the structural and electronic properties, offering directions for the discovery and design of materials with an enhanced BPVE.

Investigation of structural, mechanical, electronic and optical responses of Ga doped aluminum arsenide for optoelectronic applications: By first principles

Owing to the rapidly increasing performance of ternary semiconductors; Aluminium Gallium Arsenide (Al1-xGaxAs; x = 0, 0.25, 0.50, 0.75) has been studied by first-principles calculations in Cambridge Serial Total Energy Package (CASTEP-Code). Density functional theory in the frame of full potential linear augmented plane wave (FP-LAPW) is used. The structural, electronic, and optical behavior of the Zinc Blend (ZB) structure of AlAs with Ga impurity was computed by using generalized gradient approximation (GGA) as exchange potential and Perdew-Burke-Ernzerhof (PBE) as functional. Changes in lattice parameters (a), bulk modulus (66.07–76.85), hardness (5.79–8.91) and machinability (1.36–1.46), band gap energy (Eg), and optical properties are computed and discussed in this work. Lattice parameters and elastic constants showed excellent agreement with the reported data whereas some properties were found to excel much more than the theoretical reports. Remarkable bandgap reduction from 1.7eV to 0.28eV is very encouraging in its low-energy applications in UV and visible ranges. Real (Re) and Imaginary (Img) parts of the dielectric function and refractive index shifts towards lower energy values show good agreement with those of theoretical and experimental works. We contribute to the knowledge and characterization of Al1-xGaxAs facilitating its integration into various technological advancements such as photovoltaic, laser, diodes, and high-frequency transistors.

The impact of thickness-related grain boundary migration on hole concentration and mobility of p-type transparent conducting CuI films.

CuI films present promising optoelectronic properties for transparent conductors. However, the high hole concentration in CuI films hinders the controllable modulation of hole mobility, limiting their application in low-dimensional thin-film transistors. In this study, CuI films were prepared through a Cu film iodination method at room temperature, and a systematic investigation was conducted on the modulation of hole concentration and mobility with varying film thickness. The films exhibited a zinc blende structure (γ-phase) with increasing grain size as the thickness increased. The transmittance and optical bandgap of the films decreased with increasing thickness. The correlation of vacancy concentration with changing film thickness was analyzed through photoluminescence spectroscopy, revealing the influence of grain boundary migration on vacancy formation. The reduction in film thickness diminishes the migration of CuI grain boundaries, consequently reducing the probability of Cu vacancy and I vacancy formation, resulting in diminished hole concentration and enhanced hole mobility and film conductivity. The film with a thickness of 20 nm demonstrated optimal performance, with a transmittance of 90%, hole concentration of 4.09 × 1017 cm-3, hole mobility of 506.50 cm2 V-1 s-1, and conductivity of 33.19 S cm-1. This work deepens the understanding of hole transport such as hole concentration and mobility modulation in CuI films, highlighting the importance of controlling grain boundary migration during the film growth process.

Nano structural and opto-magnetic investigation of Co–Ni co-doped ZnSe for spintronics

Cobalt and Nickel co-doped ZnSe nanoparticles with fixed concentration of nickel and varying concentration of cobalt formulated as Zn0.95-xCoxNi0.05Se(where x = 0.0, 0.01, 0.03, 0.05) are synthesized by using wet-chemical route by co-precipitation method at 60 °C and calcined at 200 °C temperature. The structural study is carried out by applying X-ray diffractometer (XRD) characterization technique and found the synthesized material having crystallite size in nanometer range 08–37 nm with cubic zinc blende structure. Size increment of nanoparticles has been obtained as the concentration of cobalt was increased. Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Diffractometer (EDX) and Transmission-Electron Microscopy (TEM) analysis of the nanoparticles are performed to study morphology and confirming presence of doped elements by forming Cobalt and Nickel co-doped ZnSe nanoparticles. Fourier-Transform Infrared (FTIR) study is carried out to detect presence of different functional groups, bending and stretching in molecules. Energy band gap is also calculated using UV–Visible spectroscopy and found increment in band gap due to quantum confinement effect. Ferromagnetism is recorded in these Co and Ni co-doped ZnSe nanoparticles using Vibrating-Sample Magnetometer (VSM) characterization technique at 300 K and 15 K.This inducted magnetism is due to the presence of exchange interactions between electrons of different elements. Electron spin resonance (ESR) spectra is also recorded at room temperature by the presence of paramagnetic defects in the samples.

Establishing Cash-Waqf Model for Infrastructure Funding: The Analytic Network Process Study

This research aims to build a cash waqf governance framework that incorporates blended finance to develop the infrastructure in Nusantara, which is the proposed future capital city of Indonesia. Data was collected through a combination of interviews with eight informants and a survey administered to thirty respondents. The acquired data was analyzed using a mixed method that included the thematic evaluation and the analytic network process. The present study posits that the utilization of cash waqf, as a form of innovative financing mandated by the government, holds potential for the development of health infrastructure in the newly established capital of the nation. The findings of this study have significant implications for the development of policies aimed at adopting the blended finance governance structure required by the government.

The Effect of Composition and Structure of NBR-Based Elastomer Blends in the Vulcanization Process and Study of Their Aging by Exposure to Heat and Radiation

The vulcanization process of elastomeric blends based on chlorinated aromatic nitrile-butadiene rubber (SKN-40M) has been studied in the present work. The structural parameters (molecular weight, plasticity, rigidity, number of network chains, cross-linked molecules) in thermovulcanizates were investigated on an example of nitrile-butadiene rubber blend with polyvinyl chloride using viscometry and the sol-gel process.

First principles phase diagram and electronic structure estimation of ZnO1-xSex photoanodes

Terminal solid solutions in the ZnO1−xSex system (0≤x≤0.15,0.95≤x≤1) exhibit extreme bandgap reduction attributable to band anti-crossing (BAC). In this work, we perform a theoretical investigation of alloying in this system (0≤x≤1). The temperature-composition phase diagram of ZnO1−xSex is obtained via first principles and cluster expansion-based Monte–Carlo simulations. For 0≤x≤0.05, a solid solution in the wurtzite structure and for 0.5≤x≤1, a solid solution in the sphalerite structure is obtained. The alloy system exhibits a miscibility gap in the range of 0.05≤x≤0.5. Only the solid solutions are seen to obey bandgap reduction predicted by BAC. The bandgap of the alloys, calculated using the Δ-sol method, shows a bowing behavior as predicted by the BAC model. Difference in the electronegativities of O and Se atoms in the lattice leads to hybridization of O-2p and Se-4p electronic states. Interaction between these electronic states also leads to a split in the valence band edge at the O-rich end and a split in the conduction band edge at the Se-rich end. The effective mass, estimated from the density of states, of holes at the O-rich end and that of electrons at the Se-rich end, increases with alloying. These fundamental insights should help in choosing suitable alloy compositions for optimal photocurrent density when these materials are used as photoanodes.

Lexical Shortening and Blending: An Innovative Word Formation Process in Arabic

A corpus of 170 partial Arabic blends in which the first and/or second constituents are shortened was collected from several Arabic resources and subjected to further analysis to explore the structure of Arabic partial blends; blend types (attributive/headed); which constituents and which part is shortened; the kind of relation that exists between the constituents of Arabic blends; and the contexts or registers which favour the formation of lexical blends. Blends consist of two or more words merged into one new word. Blending involves shortening of one constituent or both. It involves creating new words by omitting part of the original word but retaining its original meaning. Partial blends consist of a splinter, i.e. shortened constituent (تركو Turko; انجلو Ango, افرو Afro, قطر Qatar, ايبرو Iberian, أورو Euro,يهو Jewish, أحيو biology, القرو-وسطي , أمنو security, سع Saudi, جمهو republic) and a head (full constituent) that combines with it. Data analysis showed the following: (i) compounds with multiple blends with different splinters from the same lexical items (فَحْم السكر carbon+sugar > فَحْمَس ،فَسْكَر ،فَحْسك ، فَحْكَر); (ii) blends with a final reduction in the first constituent كهرمغنيطيسي) electromagnetic(; (iii) blends with a splinter as a first constituent+the combining vowel /o/ (تركوخليجي Turkish+Gulf; هندو إيراني Indo-Iranian); (iv) three-and four-constituent blends (الأنجلو-صهيو-فارسي-أمريكي Anglo+Zio+ Persian+American); (v) Blends with prefixes that are shortened particles/adverbs (قبتاريخ pre-historic; بيسطري interlinear; فوبنفسجي ultraviolet; غِبُّلوغ post puberty; تحبحري undersea); (vi) blends with initial reduction in the second constituent resulting in the suffix {el} (امريكائيل) America+el last syllable in Israel); (vii) splinters with initial reduction in the second constituent (بيروتشيما Beirut +Hiroshima; عبقريشتاين (genius+Einstein); (viii) imperfect blends with final reduction of first constituent + initial reduction of second constituent (متشائل pessimist+optimist; جزائسطينية Algeria+Palestinian); (ix) technical blends (برمجاني freeware; حَمْضَلون acid+vinegar); and (ix) blends with overlapping consonants (أنفمي nose+mouth; عربيزي Arabic+English; قببلوغ (قبل+بلوغ) pre-puberty; سوداناس Sudan people). Syntactically and semantically, the relation between constituents of a blend containing a prefix/suffix is exocentric and syntagmatic but it is endocentric and paradigmatic in blends in most of the categories. Recommendations for testing the Arabic blend recognition, comprehension and interpretation by translation students are given.

Magnitouprugost' yan-tellerovskoy podsistemy v kristallakh tipa AIIBVI, dopirovannykh khromom

The influence of an external magnetic field on the complex elastic moduli of crystals with a sphalerite or zinc blende (ZnSe) and wurtzite (CdSe) structure lightly doped by Cr2+ ions has been investigated. Measurements have been performed in the frequency interval 26–32 MHz at 1.4 K. In II–VI crystals, bivalent chromium cations are triply orbital-degenerate in the ground state and, being in a tetrahedral environment, produce Jahn–Teller complexes. These complexes are described in terms of the T ⊗ (e + t2)-problem and exhibit the adiabatic potential energy surface with the global minima of tetragonal symmetry. It has been found that in ZnSe:Cr2+ crystals, a magnetic field directed along the [001] and [110] axes influences modulus (c11 – c12)/2 and does not influence modulus c44. In CdSe:Cr2+ crystals, however, moduli c55 and c66, which are the analogs of (c11 – c12)/2 and c44, depend on the magnetic field directed along the [101¯0101¯0] and [21¯1¯021¯1¯0] axes, respectively. The discovered anomalous behavior of the elastic moduli with magnetic field has been treated in terms of a model that takes into account the crystal field, vibronic and spin-orbital interactions, and the contribution of the Jahn–Teller subsystem to isothermal moduli determined at a constant magnetic induction. Good agreement with experimental dependences of the elastic moduli in strong magnetic fields has been obtained, and it has been shown that the nonmonotonic variation in weak magnetic fields (below 2 T) should be associated with a magnetic field dependence of the relaxation time.

Exploring Greenockite: Occurrences and Geological Setting

Greenockite, mineral containing cadmium, is of significant scientific interest owing to its remarkable properties and potential applications in the field of science. It commonly forms in hydrothermal ore deposits as a secondary mineral due to complex cadmium-sulfur interactions influenced by temperature. Typically, it replaces zinc minerals like sphalerite, depending on the abundance of cadmium and zinc in hydrothermal fluids. Solid solubility in the ZnS CdS system occurs at high temperatures, with immiscibility observed under specific conditions. Greenockite forms at relatively low temperatures (100°C to 200°C) and is influenced by factors such as oxygen fugacity, hydrogen sulfide activity, and chloride ion content. Its hexagonal zinc blende structure results in diverse crystal forms, including rods, wires, and whiskers, often adorned with bismuth drops. Experimental studies have identified factors affecting its formation, such as solid solubility, precipitation mechanisms, pH levels, and fluid composition. Its vibrant coloration, attributed to cadmium concentration, varies from pale yellow to deep orange-red. Geologically, it is present in diverse settings, including metamorphosed zinc oxide mineralization, granites, fumaroles, pegmatites, and sediment-hosted Pb-Zn deposits, with a unique occurrence in gabbroic rock at the Babbitt deposit. In India, Greenockite has been identified in the Bagada orogenic gold prospect, situated within the Paleoproterozoic Mahakoshal belt, Central Indian Tectonic Zone (CITZ). Additionally, it is found in hydrothermal deposits of Pb-Zn mines of Zawar. It is exclusively encountered within specific geological settings, primarily as a secondary product. This paper provides a comprehensive exploration of its geological occurrences, distribution, associations, and exceptions.

Acid selenites as new selenium precursor for CdSe quantum dot synthesis

Chemical precursors for nanomaterials synthesis have become essential to tune particle size, composition, morphology, and unique properties. New inexpensive precursors investigation that precisely controls these characteristics is highly relevant. We studied new Se precursors, the acid selenites (R–O–SeOOH), to synthesize CdSe quantum dots (QDs). They were produced at room temperature by the ▪ reaction with alcohols having different alkyl chains and were characterized by 1H NMR confirming their structures. This unprecedented precursor generates high-quality CdSe nanocrystals with narrow size distribution in the zinc-blend structure showing controlled optical properties. Advanced characterization detailed the CdSe structure showing stacking fault defects and its dependence on the used R–O–SeOOH. The QDs formation was examined using a time-dependent growth kinetics model. Differences in the nanoparticle surface structure influenced the optical properties, and they were correlated to the Se-precursor nature. Small alkyl chain acid selenites generally lead to more controlled QDs morphology, while the bigger alkyl chain leads to slightly upper quantum yields. Acid selenites can potentially replace Se-precursors at competitive costs in the metallic chalcogenide nanoparticles. ▪ is chemically stable, and alcohols are cheap and less toxic than the reactants used today, making acid selenites a more sustainable Se precursor.

Growth and characterization of large-size CdMgTe single crystals doped with different in amounts

Cadmium magnesium telluride (CdMgTe) is a very perspective material for room temperature radiation detectors. In this paper, two large-size Cd0.95Mg0.05Te ingots doped with different In amounts were grown by vertical Bridgman method under Cd-compensated condition. It was found that the impurities were distributed inhomogeneously and In dopant mainly concentrated in the tail of two ingots. Compared with the ingot grown by doping with 5 ppm In, the ingot grown by doping with 10 ppm In had more uniform distribution of Mg element, higher IR transmittance, less Te inclusions and better crystal quality. FIB-TEM and HRTEM analysis showed that the size of Te precipitates was less than 10 nm, the composition of both crystals was rich in Cd and was single crystal with sphalerite structure. The type of dislocation was edge dislocation and the density was high. In addition, the maximum IR transmittance and highest resistivity were 64 % and 1.53 × 1010 Ω cm, respectively. The planar detector prepared with 10 ppm In doped crystal had an energy resolution of 19.6 % and a (μτ)e value of 1.38 × 10−3 cm2/V, which could meet the requirements for high performance room-temperature radiation detector.

Theoretical investigation of optoelectronic properties of Al-doped BAs using TB-mBJ approach

For quite a long time, the scientific community has been searching for a material that surpasses the existing material systems in terms of energy conversion efficiency for photovoltaic applications. In this study, the optoelectronic properties of pure and Al-doped boron arsenide B[Formula: see text]Al[Formula: see text]As [Formula: see text] in the zinc blende (ZB) structure were systematically examined using the density functional theory (DFT) and the Modified Becke–Johnson (TB-mBJ) exchange correlation (XC) potential. The Perdew–Burke–Ernzerhof generalized gradient approximation (PBE) functional was used for structural optimization. After considering the ground state lattice constant of 4.82[Formula: see text]Å then calculating the bandgap energy of pure BAs, which are consistent with experimental and theoretical findings, we estimated the basic electronic and optical characteristics of Al-doped boron arsenide, including band structures, electronic density of state, dielectric function, refractive index, extinction coefficient, absorption and optical conductivity. The unusual and interesting optoelectronic features of the investigated compounds revealed in this work offer substantial promise for improving the energy conversion efficiency of solar cells.

Piezoionic High Performance Hydrogel Generator and Active Protein Absorber via Microscopic Porosity and Phase Blending.

Generating electricity in hydrogel is very important but remains difficult. Hydrogel with electricity generation capability is more capable in bio-relevant tasks such as tissue engineering, artificial skin, or medical treatment, because electricity is indispensable in regulating physiological activities. Here, a porous and phase blending hydrogel structure for effective piezoionic electricity generation is developed. Dynamic electric field is generated taking advantage of the difference in streaming speeds of sodium and chloride in the material. Microscopic porosity and hydrophilic-hydrophobic phase blending are the two key factors for prominent piezoionic performance. Voltages as high as 600mV are first realized in hydrogels in response to medical ultrasound stimulation. The hydrogel structure is also subjective to effective substance exchange and can actively enrich proteins from surroundings under mechanical stimuli. Preliminary applications in neural stimulation, constructing complex spatial-temporal chemical and electric field distribution patterns, mimetic tactile sensor, sample pretreatment in fast detection, and enzyme immobilization are demonstrated.

Optical and Color Investigation of the Effect of Laser Radiation on Polyaniline/Polyvinyl Pyrrolidone/Zinc Sulfide Nanocomposite Films

A nanocomposite (NC) of polyaniline (Pani), polyvinyl pyrrolidone (PVP) and zinc sulfide (ZnS) nanoparticles (NP) was prepared using chemical coprecipitation and ex-situ casting procedures. ZnS NP were synthesized using the chemical coprecipitation technique in atmospheric air. The x-ray diffraction (XRD) scans indicated that the synthesized ZnS had a nanonature and fit the cubic zinc blended structure. We used an infrared pulsed laser to irradiate the Pani/PVP/ZnS NC samples with fluences ranging from 3 to18 J/cm2. The induced changes in the NC were investigated using the UV spectroscopy and International Commission on Illumination (CIE) color difference methodology. When the laser fluence increased up to 18 J/cm2 both the direct and indirect optical bandgaps (Eg) decreased. Additionally, we used the optical dielectric loss (ε”) to detect the type of microelectronic transition for the NC samples. The Eg of the exposed NC samples and the pristine samples exhibited indirect allowed transitions. The laser effects on the absorbance, extinction coefficient, transmission, refractive index, dielectric parameters and optical conductivity of the NC were studied. Lastly, the color differences between the pristine and exposed samples were determined. The pristine Pani/PVP/ZnS showed a significant color difference with the laser irradiated samples. The changes of the studied optical parameters with the laser fluence indicated that the laser radiation represents a convenient tool that would allow the application of Pani/PVP/ZnS NC in optoelectronic devices.

Study of structural, morphological and optical properties of Mn+2 doped CdS nanoparticles synthesized at various doping concentration

Manganese-doped cadmium sulphide semiconductor nanoparticles (CdS: Mn) NPs have been created utilizing a microwave-assisted solvothermal technique at different Mn concentrations (0, 1%, 3%, and 5%). The chemicals utilized for the preparation of Mndoped CdS nanoparticles were sodium sulphide (Na2S.xH2O), manganese chloride (MnCl2.4H2O), and cadmium acetate (CH3COO)2Cd., H2O). To determine the structural dimensions of the generated nanoparticles, the Debye-Scherer equation was used to calculate the average crystallite size at the full-width half maximum (FWHM) of the diffraction peaks. FTIR spectra analysis was used to look at the various functional and vibrational groups present in the Mn-doped CdS nanoparticle sample. The structure features of the produced nanoparticles have been examined using X-ray diffraction patterns. Energy dispersive X-rays were employed to ascertain the chemical composition of the synthesized nanoparticles. The optical properties and quantification of the energy band gap of the nanoparticles have been done using UV-V spectroscopy. According to XRD calculations, the cubic zinc-blend structure of the generated NPs had a crystal size of between 4 and 7 nm. By using EDX spectroscopy, the incorporation of Mn at the CdS lattice was confirmed.

Microwave absorption performance of nitrile butadiene rubber/ethylene propylene diene monomer rubber filled with multiwalled carbon nanotubes

AbstractIn recent times, there is an increasing need for effective control of electromagnetic pollution, which can avoid excessive radiation effects on the human body. Microwave absorption materials are attracting wide research interests to reduce electromagnetic pollution due to the rapid development of electronic equipment. In this study, Nitrile butadiene rubber (NBR)/ethylene propylene diene monomer rubber (EPDM) were mixed with multiwalled carbon nanotubes (MWCNT) to prepare microwave absorbing materials. The distribution of fillers, AC conductivity, complex permittivity, and microwave absorption performance of the composites were systematically investigated. It found that the AC conductivity, both real and imaginary parts of the permittivity were significantly improved in the composite with the increasing ratio of MWCNT contents. The NBR/EPDM/MWCNT composites with eight parts per hundred concerning with rubber (phr) MWCNT had a minimum reflection loss (RLmin) of −48.1 dB at the optimum thickness of 2.07 mm. Importantly, the adding sequence of MWCNT and plasticizer dioctyl phthalate (DOP) to the rubber matrix is found to play an important role in determining the distribution of fillers and the structure of polymer blends. The composite with plasticizer added before MWCNT exhibited a better impedance matching and as a result, achieved a good microwave absorption performance.

Design of Sn-doped cadmium chalcogenide based monolayers for valleytronics properties

Valleytronics has emerged as an interesting field of research in two-dimensional (2D) systems and uses the valley index or valley pseudospin to encode information. Spin–orbit coupling (SOC) and inversion symmetry breaking lead to spin-splitting of bands near the valleys. This property has promising device applications. In order to find a new 2D material useful for valleytronics, we have designed hexagonal planar monolayers of cadmium chalcogenides (CdX, X = S, Se, Te) from the (111) surface of bulk CdX zinc blende structure. The structural, dynamic, mechanical and thermal stability of these structures is confirmed. A band structure study reveals valence band local maxima (valleys) at the K and K′ symmetry points. The application of SOC initiates spin-splitting in the valleys that lifts the energy degeneracy and shows strong valley–spin coupling. To initiate stronger SOC, we substituted two Cd atoms in the almost-planar monolayers with Sn atoms, which increases the spin-splitting significantly. Zeeman-type spin-splitting is observed in the valley region and Rashba spin-splitting is observed at the Γ point for Sn-doped CdSe and CdTe monolayers. Berry curvature values are higher in all the Sn-doped monolayers than in the pristine monolayers. These newly designed monolayers are thus found to be suitable for valleytronics applications. Sn-doped monolayers show band inversion deep in the valence and conduction bands between Sn s and p and X p states but lack topological properties.