New carbon allotropes in sp + sp${}^3$ bonding networks consisting of C${}_8$ cubes

Abstract

We identify by ab initio calculations a new type of three-dimensional carbon allotropes constructed by inserting acetylenic or diacetylenic bonds into a body-centered cubic C${}_8$ lattice. The resulting $sp+s{p}^3$-hybridized cubane-yne and cubane-diyne structures consisting of C${}_8$ cubes can be characterized as a cubic crystalline modification of linear carbon chains, but energetically more favorable than the simplest linear carbyne chain and the cubic tetrahedral diamond and yne-diamond consisting of C${}_4$ tetrahedrons. Electronic band calculations indicate that these new carbon allotropes are semiconductors with an indirect band gap of 3.08 eV for cubane-yne and 2.53 eV for cubane-diyne. The present results establish a new type of carbon phases consisting of C${}_8$ cubes and offer insights into their outstanding structural and electronic properties.

6 pages, 5 figures

References in corpus (3)

• Electric Field Effect in Atomically Thin Carbon Films
• Spin-orbit-free Weyl-loop and Weyl-point semimetals in a stable three-dimensional carbon allotrope
• Line of Dirac Nodes in Hyper-Honeycomb Lattices

Cited by in corpus (1)

• Carboneyane: A nodal line topological carbon with sp-sp2-sp3 chemical bonds