Novel ultrahard extended hexagonal C10, C14 and C18 allotropes with mixed sp2/sp3 hybridizations: Crystal chemistry and ab initio investigations - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Carbon Research Année : 2023

Novel ultrahard extended hexagonal C10, C14 and C18 allotropes with mixed sp2/sp3 hybridizations: Crystal chemistry and ab initio investigations

Résumé

Based on 4H, 6H and 8H diamond polytypes, novel extended lattice allotropes C10, C14 and C18 characterized by mixed sp3/sp2 carbon hybridizations were devised based on crystal chemistry rationale and first-principles calculations of the ground state structures and energy derived properties: mechanical, dynamic (phonons), and electronic band structure. The novel allotropes were found increasingly cohesive along the series, with cohesive energy values approaching those of diamond polytypes. Regarding mechanical properties, C10, C14, and C18 were found ultrahard with Vickers hardness slightly below that of diamond. All of them are dynamically stable, with positive phonon frequencies reaching maxima higher than in diamond due to the stretching modes of C=C=C linear units. The electronic band structures expectedly reveal the insulating character of all three diamond polytypes and the conductive character of the hybrid allotropes. From the analysis of the bands crossing the Fermi level, a nesting Fermi surface was identified, allowing us to predict potential superconductive properties.
Fichier principal
Vignette du fichier
C_Polytypes-and-hybrids (HAL).pdf (1.48 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Licence : CC BY - Paternité

Dates et versions

hal-03947749 , version 1 (20-01-2023)

Identifiants

Citer

Samir Matar, Volker Eyert, Vladimir Solozhenko. Novel ultrahard extended hexagonal C10, C14 and C18 allotropes with mixed sp2/sp3 hybridizations: Crystal chemistry and ab initio investigations. Journal of Carbon Research, 2023, 9 (1), pp.11. ⟨10.3390/c9010011⟩. ⟨hal-03947749⟩
7 Consultations
15 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More