{"title":"Superhard Hexagonal sp3-Bonded BN Polytypes and BC2N from Crystal Chemistry and First Principles","authors":"Samir F. Matar, Vladimir L. Solozhenko","doi":"10.3103/S1063457624020060","DOIUrl":null,"url":null,"abstract":"<p>In the framework of a crystallochemical approach, new hexagonal (<i>P</i>6<sub>3</sub>/<i>mc</i>) <i>sp</i><sup>3</sup>-bonded BN polytypes (4H, 6H and 8H) and ternary BC<sub>2</sub>N were proposed by rationalized substitutions of C for B and N in hexagonal carbon allotrope C<sub>8</sub> (4C carbon) with cfc topology, and density functional theory calculations of their ground states were performed. All new phases were found to be cohesive and stable mechanically (elastic constants) and dynamically (phonon band structures). According to modern models of hardness, the new phases were recognized as superhard with Vickers hardness above 50 GPa. Their electronic band structures exhibit insulating behavior with large band gaps.</p>","PeriodicalId":670,"journal":{"name":"Journal of Superhard Materials","volume":"46 2","pages":"81 - 93"},"PeriodicalIF":1.2000,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Superhard Materials","FirstCategoryId":"88","ListUrlMain":"https://link.springer.com/article/10.3103/S1063457624020060","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
In the framework of a crystallochemical approach, new hexagonal (P63/mc) sp3-bonded BN polytypes (4H, 6H and 8H) and ternary BC2N were proposed by rationalized substitutions of C for B and N in hexagonal carbon allotrope C8 (4C carbon) with cfc topology, and density functional theory calculations of their ground states were performed. All new phases were found to be cohesive and stable mechanically (elastic constants) and dynamically (phonon band structures). According to modern models of hardness, the new phases were recognized as superhard with Vickers hardness above 50 GPa. Their electronic band structures exhibit insulating behavior with large band gaps.
期刊介绍：
Journal of Superhard Materials presents up-to-date results of basic and applied research on production, properties, and applications of superhard materials and related tools. It publishes the results of fundamental research on physicochemical processes of forming and growth of single-crystal, polycrystalline, and dispersed materials, diamond and diamond-like films; developments of methods for spontaneous and controlled synthesis of superhard materials and methods for static, explosive and epitaxial synthesis. The focus of the journal is large single crystals of synthetic diamonds; elite grinding powders and micron powders of synthetic diamonds and cubic boron nitride; polycrystalline and composite superhard materials based on diamond and cubic boron nitride; diamond and carbide tools for highly efficient metal-working, boring, stone-working, coal mining and geological exploration; articles of ceramic; polishing pastes for high-precision optics; precision lathes for diamond turning; technologies of precise machining of metals, glass, and ceramics. The journal covers all fundamental and technological aspects of synthesis, characterization, properties, devices and applications of these materials. The journal welcomes manuscripts from all countries in the English language.
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