Strain tunable band structure of a new 2D carbon allotrope C₅₆₈

Abstract

Recently, C568 has emerged as a new carbon allotrope, which shows semiconducting properties with a band gap around 1 eV and has attracted much attention. In this work, the external strain effects on the electronic properties of C568 have been studied theoretically through first-principle calculations. The numerical results show that while in-plane uniaxial and biaxial strains both reduces the band gap of C568 in case of tensile strain, their effects are quite different in the case of compressive strain. With increasing compressive uniaxial strain, the band gap of C568 first increases, and then dramatically decreases. In contrast, the application of compressive biaxial strain up to –10% only leads to a slight increase of band gap. Moreover, an indirect-to-direct gap transition can be realized under both types of compressive strain. The results also show that the optical anisotropy of C568 can be induced under uniaxial strain, while biaxial strain does not cause such an effect. These results indicate good strain tunability of the band structure of C568, which could be helpful for the design and optimization of C568-based nanodevices.

Density Function Theory Predicted Carbon Allotropes: Recent Developments

“…Another important example of this class is curved 6.8 2 D carbon (Figure 32), which is an indirect bandgap semiconductor with a 3D structure consisting of all sp 2 hybridized carbon atoms (electrons are localized in the middle of C−C bonds) with negative curvature and high‐temperature dynamic stability [88] . A DFT‐predicted 2D carbon allotrope C 568 with semiconducting properties (band gap ∼1 eV) is found to be useful for the design and optimization of C 568 ‐based nanodevices [89] . Another 2D carbon allotrope Po‐C32 containing 32 atoms, which is made up of 5‐, 6‐, 8‐ and 10‐member rings with P4/MMM symmetry and a vertical distance of 2.22 Å between the uppermost and undermost atoms is also found to exhibit semiconducting properties [90] .…”

“…[88] A DFT-predicted 2D carbon allotrope C 568 with semiconducting properties (band gap ∼ 1 eV) is found to be useful for the design and optimization of C 568 -based nanodevices. [89] Another 2D carbon allotrope Po-C32 containing 32 atoms, which is made up of 5-, 6-, 8-and 10-member rings with P4/MMM symmetry and a vertical distance of 2.22 Å between the uppermost and undermost atoms is also found to exhibit semiconducting properties. [90] The C 568 structure was shown to be suitable for the charging and discharging process in LIBs (Li adsorption energy over a fully-charged C 568 monolayer is À 0.25 eV; the barrier is 0.42 eV for Li diffusion).…”

Theoretical Study on (n,n)-Nanotubes Rolled-up from B/N Substituted Me-Graphene

“…Me-graphene is a semiconductor with an indirect band gap of 2.04 eV. Further investigations indicate that its physical features can be effectively regulated by stacking, strains, hydrogenation, adsorption, and many other methods [37][38][39][40][41]. Using Me-graphene as a template, some of new 2D materials can be designed.…”

Two-dimensional graphyne–graphene heterostructure for all-carbon transistors

“…as reliable substitutes to the silicon has long been a topic of interest. Lots of 2D carbon materials have been synthesized or predicted, such as graphene [11], graphyne [12,13], T-graphene [14], penta-graphene [15], and C568 [16,17]. Graphene is the most famous 2D carbon materials due to its unique electronic and mechanical properties [11,18,19], but the gapless band structure limits its wide application in serving as the channel of field-effect transistors.…”