The electronic structure of GaSe/silicane (GaSe/SiH) van der Waals (vdW) heterostructure in response to a vertical electric field and strain was studied via first-principle calculations. The heterostructure had indirect band gap characteristics in the range [&#x2212;1.0, &#x2212;0.4] V/&#xc5; and direct band gap features in the range [&#x2212;0.3, 0.2] V/&#xc5;. Furthermore, a type-II to type-I band alignment transition appeared at &#x2212;0.7 and &#x2212;0.3&#x2009;V/&#xc5;. Additionally, the GaSe/SiH vdW heterostructure had a type-II band alignment under strain, but an indirect to direct band gap semiconductor transition occurred at &#x2212;3&#x0025;. These results indicated that the GaSe/SiH vdW heterostructure may have applications in novel nanoelectronic and optoelectronic devices.

Gang Xu

Hao Lei

Tuning Electronic Properties of GaSe/Silicane Van der Waals Heterostructure by External Electric Field and Strain: A First-Principle Study

The permeability and electrical resistivity of barium hexaferrite magnetic materials can be used in various products such as magnetic recording media, computers, electronic devices, materials for permanent magnets, and communication devices. This work focuses on the synthesis of rare earth lanthanum (La<sup>3&#x2b;</sup>)-doped manganese in barium hexaferrite (Ba<sub>1&#x2212;<i>x</i></sub>La<sub><i>x</i></sub>Mn<sub><i>y</i></sub>Fe<sub>12&#x2212;<i>y</i></sub>O<sub>19</sub>) (<i>x</i>&#x2009;&#x3d;&#x2009;0.02&#x2013;0.10 and <i>y</i>&#x2009;&#x3d;&#x2009;0.02&#x2013;0.10) prepared by using the coprecipitation method. The intensity peak is increased with increasing the concentration of lanthanum, which shows the enhancement in the degree of crystallinity and increase in the size of crystallite. The band gap energy decreased gradually with the increase of concentration of lanthanum. The micrographs observed that the material is basically made up of some rings or rods such as particles in pure La-Ma in barium hexaferrite. The agglomeration was observed because of heat behavior at 600&#xb0;C or may be concentration effect. The structural studies are done using X-ray diffraction, UV, FT-IR, and SEM techniques.

Meshal Alzaid

Enhancement in Optical Properties of Lanthanum-Doped Manganese Barium Hexaferrites under Different Substitutions

In recent years, some laboratories have been able to prepare calcium hydrobromide (CaHBr) by melting hydride and anhydrous bromide or metal and bromide in a hydrogen atmosphere at 900°C and have studied some of its properties. But there are few theoretical studies, especially the theoretical studies of monolayer CaHBr. We use the first-principles method to calculate the structure, elastic properties, and lattice thermal conductivity of the monolayer CaHBr based on the Boltzmann transport equation. We obtain a stable crystal structure by the optimization of monolayer CaHBr. By calculating the elastic constant of monolayer CaHBr, its mechanical stability is proved, and the elastic limit of monolayer CaHBr is obtained by biaxial tensile strain on monolayer CaHBr. And the corresponding phonon spectra show no imaginary frequency, indicating the dynamic stability of the monolayer CaHBr. By the ShengBTE code, we calculate the lattice thermal conductivity of the monolayer CaHBr, the iterative solution of BTE and RTA at 300 K–1200 K is obtained, and the lattice thermal conductivity at room temperature is <span class="inline_break"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" width="34.457pt" style="vertical-align:-3.9435pt" id="M1" height="15.8272pt" version="1.1" viewBox="-0.0498162 -11.8837 34.457 15.8272"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-232" d="M484 406C484 429 465 448 438 448C400 448 352 405 302 356L156 213L191 373C195 391 197 404 197 416C197 436 191 448 178 448C151 448 83 406 23 350L37 328C67 350 101 369 109 369C114 369 115 362 111 344L29 -5L34 -12C63 -5 86 -1 111 3C124 73 137 138 147 161C165 180 189 202 206 217C215 194 249 111 275 57C304 -1 319 -12 342 -12C368 -12 405 -5 471 92L454 115C427 80 395 55 384 55C374 55 364 58 341 106L262 274C282 296 367 378 414 378C427 378 440 370 444 367C449 363 454 362 462 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It can be seen that the lattice thermal conductivity of monolayer CaHBr is low. And by analyzing the phonon spectrum, the scattering rate, and the mean free path of the phonons, the lattice thermal conductivity of monolayer CaHBr mainly depends on the acoustic modes. We hope this study can provide theoretical guidance for the experiments and practical application of monolayer CaHBr.

Si-Hua Li

Cui-E Hu

Xiao-Lu Wang

Yan Cheng

First-Principles Study of Structure, Elastic Properties, and Thermal Conductivity of Monolayer Calcium Hydrobromide

The large-scale production of high-quality graphene is the major focus of scientists and engineers recently. However, its massive manufacturing routes from its precursor graphene oxide (GO) are involved in the production of toxic gasses and consist of hazardous explosive steps that severely hurt and threaten ecological balance and human health. Therefore, in this study, we investigated the green, effective, and economical approach for the synthesis of graphene by using <i>Vernonia amygdalina</i> (VA) plant leaf extracts for the effective and efficient reduction of GO. The nonexplosive two-step synthesis of GO in a short period of time in the absence of an ice bath was used in this study. The appropriate solvent for the extraction of VA for the green synthesis of graphene was methanol, and the reducing and capping agent in the plant extract was identified to be terpenoids and polyphenols. The graphene/rGO obtained this way was characterized by UV-VIS, XRD, FTIR, SEM, HR-TEM, and EDAX that confirmed the successful reduction of GO to graphene under the hydrothermal process. The HR-TEM images showed the development of few layers of graphene. The FTIR result also shows the complete reduction of GO. Hence, methanol extracted VA leaves consisted of the most appropriate compounds for reducing and capping agent in the green synthesis and could be the preferred method for the large-scale production of graphene-based materials.

Bayisa Meka Chufa

Bedasa Abdisa Gonfa

Teketel Yohannes Anshebo

Getachew Adam Workneh

A Novel and Simplest Green Synthesis Method of Reduced Graphene Oxide Using Methanol Extracted <i>Vernonia Amygdalina</i>: Large-Scale Production

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<p><em>Advances in Condensed Matter Physics</em> publishes research on the experimental and theoretical study of the physics of materials in solid, liquid, amorphous, and exotic states.</p>


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<p>Chief Editor, Professor Ulloa, is based at Ohio University and is a condensed matter theorist. His research is focussed on the electronic properties of nanostructures including quantum dots and nanowires, as well as proximity effects in 2D crystals.</p>


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Advances in Condensed Matter Physics