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

TL;DR

This paper predicts a new stable carbon allotrope called carboneyane, featuring unique topological properties, mixed hybridization bonds, and potential applications in storage and electrode materials, based on first-principles calculations.

Contribution

It introduces carboneyane, a novel carbon allotrope with combined sp, sp2, and sp3 bonds, and explores its topological and structural properties.

Findings

Carboneyane is a topological metal with nodal lines.

It has a low density of 1.43 g/cm3 and good ductility.

X-ray diffraction peaks match experimental soot samples.

Abstract

A structurally stable carbon allotrope with plentiful topological properties is predicted by means of first-principles calculations. This novel carbon allotrope possesses the simple space group C2/m, and contains simultaneously sp, sp2 and sp3 hybridized bonds in one structure, which is thus coined as carboneyane. The calculations on geometrical, vibrational, and electronic properties reveal that carboneyane, with good ductility and a much lower density 1.43 g/cm3, is a topological metal with a pair of nodal lines traversing the whole Brillouin zone, such that they can only be annihilated in a pair when symmetry is preserved. The symmetry and topological protections of the nodal lines as well as the associated surface states are discussed. By comparing its x-ray diffraction pattern with experimental results, we find that three peaks of carboneyane meet with the detonation soot. On account of the fluffy structure, carboneyane is shown to have potential applications in areas of storage, adsorption and electrode materials.