Electronic and optical properties of novel carbon allotropes

TL;DR

This study uses first-principles calculations to explore the phonon, electronic, and optical properties of novel carbon allotropes, confirming their stability and potential for optoelectronic applications.

Contribution

It provides new insights into the stability and electronic properties of monolayer and double-layer penta-graphene and T12-carbon, expanding understanding of their potential uses.

Findings

Exotic carbon allotropes are dynamically stable.

Bulk T12 is an indirect-gap semiconductor (~4.89 eV).

Monolayer and double-layer PG are quasi-direct gap semiconductors (~2.64 eV and ~3.27 eV).

Abstract

The phonon properties, electronic structures and optical properties of novel carbon allotropes, such as monolayer penta-graphene (PG), double-layer PG and T12-carbon, were explored by means of first-principles calculations. Results of phonon calculations demonstrate that these exotic carbon allotropes are dynamically stable. In addition, the bulk T12 phase is an indirect-gap semiconductor having a bandgap of ~4.89 eV. Whereas the bulk material transforms to a 2D phase, the monolayer and double-layer PG become quasi-direct gap semiconductors with smaller band gaps of ~2.64 eV and ~3.27eV, respectively. Furthermore, the partial charge density analysis indicates that the 2D phases retain part of the electronic characteristics of the T12 phase. The linear photon energy-dependent dielectric functions and related optical properties including refractive index, extinction coefficient, absorption spectrum, reflectivity, and energy loss spectrum were also computed and discussed. The structural estimation obtained as well as other findings are in agreement with existing theoretical data. The calculated results are beneficial to the practical applications of these exotic carbon allotropes in optoelectronics and electronics.