A superconducting boron allotrope featuring anticlinal pentapyramids

Abstract

Finding allotropes with novel structures and intriguing properties is of great interest from both fundamental and applicable standpoints. Here, we propose a hitherto unknown boron allotrope, possessing intrinsic superconductivity and...

Prediction of novel boron–carbon based clathrates

“…Although both of them have negative formation enthalpy with respect to the pure elemental substances, 19,[43][44][45][46] they are metastable compounds compared with the energetically favorable binary and ternary phases. 19,22,[47][48][49][50][51] According to the different synthesis routes as listed in Tables S2 and S3 (ESI †), most compounds have formation enthalpies less than 50 meV per atom that is within the range of experimental synthesis (B50 meV). 52 For SrB 2 C 4 , the synthesis route with SrB 2 and diamond/ graphite carbon as reactants exhibits a negative formation enthalpy of À31.6/À289.2 meV per atom at 50 GPa.…”

Clathrate‐Like Alkali and Alkaline‐Earth Metal Borides: A New Family of Superconductors with Superior Hardness

“…Such features can lead to high electronic DOS near the Fermi level, raising possibility of the formation of Cooper pairs and strengthening the electron-phonon coupling (EPC), which thus were expected to result in superconductors. [21,[44][45][46] We further calculated the superconducting transition temperature (T c ) of CaB 7 structure by the Allen-Dynes modified McMillan equation. [47] For reasonable comparison with previously reported systems, we employed a commonly accepted value of Coulomb pseudopotential parameters (µ* = 0.1).…”

“…Such features can lead to high electronic DOS near the Fermi level, raising possibility of the formation of Cooper pairs and strengthening the electron–phonon coupling (EPC), which thus were expected to result in superconductors. [ 21,44–46 ]…”

Superconducting boron allotrope featuring pentagonal bipyramid at ambient pressure

“…This approach has also been successfully applied in searching for new boron allotropes, some of which are observed to be superconductors under ambient conditions. [12][13][14][15] (T c B 2.9 K), have also been found using a similar approach. 14,15 These binary compounds form threedimensional boron frameworks with open channels in which metal atoms are located, a structural feature that makes it easy for them to escape.…”

“…Therefore, many efforts have been devoted to study the precursors of boron allotropes. [12][13][14][15] High-pressure binary compounds with open frameworks can be used as precursors to obtain elemental allotropes via physical and chemical manipulations. For example, removing sodium and helium from the pressure-induced binary phases of P6/m NaSi 6 , Cmcm Na 4 Si 24 , and I4 1 /a HeN 4 , the allotropes of P6/m Si 6 , 16 Cmcm Si 24 17 and t-N 18 were achieved to be stable at ambient pressure, respectively.…”