Novel Two-dimensional Carbon Allotrope with Strong Electronic Anisotropy

TL;DR

This paper introduces two new 2D carbon allotropes with unique electronic properties, including strong anisotropy and Dirac points, expanding the potential for nano-electronic applications.

Contribution

The study proposes two novel 2D carbon structures, OPG-L and OPG-Z, with distinct electronic behaviors and explains their properties using a tight-binding model.

Findings

OPG-L is metallic.

OPG-Z is a gapless semimetal.

OPG-Z exhibits highly anisotropic Dirac points.

Abstract

Two novel two-dimensional carbon allotropes comprised of octagons and pentagons are proposed based on the first-principles calculations. The two carbon allotropes, named OPG-L and OPG-Z, are found to have distinct properties. OPG-L is metallic, while OPG-Z is a gapless semimetal. Remarkably, OPG-Z exhibits pronounced electronic anisotropy with highly anisotropic Dirac points at the Fermi level. A tight-binding model is suggested to describe the low-energy quasiparticles, which clarifies the origin of the anisotropic Dirac points. Such an anisotropic electronic characteristic of OPG-Z is expected to have wide implications in nano-electronics.