resumo
Investigations of clathrate structures have gained a new impetus with the recent discovery of roomtemperature superconductivity in metal hydrides. Here we report the finding, through density functional theory calculations, of a clathrate phase in the fullerite C60 system. Intermolecular bonds of the type 5/5 2 thorn 3 cycloaddition are induced between each C60 molecule and its twelve nearest neighbors in the face centered cubic lattice. Remarkably, this bonding creates on octahedral sites new C60 cages, identical to the original ones, and on tetrahedral sites distorted sodalite-like cages. The resulting carbon clathrate has a Pm3 simple cubic structure with half of the original face centered lattice constant. Eighty percent of its atoms are sp3-hybridized, driving a narrow-gap semiconducting behavior, a moderate bulk modulus of 268 GPa and an estimated hardness of 21.6 GPa. This new phase is likely to be prepared by subjecting C60 to high pressure and high temperature conditions. (c) 2022 Elsevier Ltd. All rights reserved.
palavras-chave
AMORPHOUS-CARBON; HIGH-PRESSURE; SUPERCONDUCTIVITY; CRYSTALLINE; PHASES
categoria
Chemistry; Materials Science
autores
Laranjeira, J; Marques, L; Melle-Franco, M; Strutynski, K; Barroso, M
nossos autores
Jorge Diogo Marques Laranjeira
Estudante de doutoramento
Karol Strutyński
Investigador Auxiliar
Leonel Marques Vitorino Joaquim
Professor Auxiliar
Manuel Melle-Franco
Investigador PrincipalProjectos
Projeto de Investigação Exploratória: Manuel Melle (IF Manuel Melle)
agradecimentos
This work was supported by the projects POCI-01-0145-FEDER-031326 and IF/00894/2015 financed by the Portuguese Foundation for Science and Technology (FCT) and co-financed by FEDER. CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. J. Laranjeira acknowledges a PhD grant from FCT (SFRH/BD/139327/2018) .