T-Carbon: A Novel Carbon Allotrope

TL;DR

This paper predicts a new stable carbon allotrope called T-carbon, which is a semiconductor with unique structural and electronic properties, potentially useful for various technological applications.

Contribution

First-principles calculations predict a novel, stable T-carbon allotrope with unique properties and potential applications, expanding the understanding of carbon materials.

Findings

T-carbon is structurally stable with a low density of 1.50 g/cm3.

It is a semiconductor with a direct band gap of about 3.0 eV.

T-carbon has a Vickers hardness comparable to cubic boron nitride.

Abstract

A structurally stable crystalline carbon allotrope is predicted by means of the first-principles calculations. This allotrope can be derived by substituting each atom in diamond with a carbon tetrahedron, and possesses the same space group Fd^1 3m as diamond, which is thus coined as T- carbon. The calculations on geometrical, vibrational and electronic properties reveal that T-carbon, with a considerable structural stability and a much lower density 1.50 g/cm3, is a semiconductor with a direct band gap about 3.0 eV, and has a Vickers hardness 61.1 GPa lower than diamond but comparable with cubic boron nitride. Such a form of carbon, once obtained, would have wide applications in photocatalysis, adsoption, hydrogen storage and aerospace materials.