g-SiC6 Monolayer: A New Graphene-like Dirac Cone Material with a High Fermi Velocity

TL;DR

This paper predicts a new 2D silicon carbide monolayer, g-SiC6, with a high Fermi velocity and controllable Dirac cone properties, showing promise for high-performance electronic applications.

Contribution

First-principles calculations reveal a novel g-SiC6 monolayer with exceptional stability, high Fermi velocity, and tunable Dirac cones, expanding the family of 2D Dirac materials.

Findings

g-SiC6 has the highest Fermi velocity among silicon carbide Dirac materials.

The Dirac cone in g-SiC6 can be tuned by uniaxial and shear strain.

New AB6 compounds with similar structure also exhibit Dirac cones and stability.

Abstract

Two-dimensional (2D) materials with Dirac cones have been intrigued by many unique properties, i.e., the effective masses of carriers close to zero and Fermi velocity of ultrahigh, which yields a great possibility in high-performance electronic devices. In this work, using first-principles calculations, we have predicted a new Dirac cone material of silicon carbide with the new stoichiometries, named g-SiC6 monolayer, which is composed of sp2 hybridized with a graphene-like structure. The detailed calculations have revealed that g-SiC6 has outstanding dynamical, thermal, and mechanical stabilities, and the mechanical and electronic properties are still isotropic. Of great interest is that the Fermi velocity of g-SiC6 monolayer is the highest in silicon carbide Dirac materials until now. The Dirac cone of the g-SiC6 is controllable by an in-plane uniaxial strain and shear strain, which is promised to realize a direct application in electronics and optoelectronics. Moreover, we found that new stoichiometries AB6 (A, B = C, Si, and Ge) compounds with the similar SiC6 monolayer structure are both dynamics stable and possess Dirac cones, and their Fermi velocity was also calculated in this paper. Given the outstanding properties of those new types of silicon carbide monolayer, which is a promising 2D material for further exploring the potential applications.