σ–π-Band Inversion in a Novel Two-Dimensional Material

We present a theoretical study of a new type of two-dimensional material exhibiting a pentagonal arrangement of C and Si atoms. Pentagonal SiC2is investigated with density functional theory-based calculations to show that the buckled nanostructure is dynamically stable, and exhibits an indirect energy band gap and an enhanced electronic dispersion with respect to the all-carbon counterpart. Computed Born effective charges exhibit a significant anisotropy for C and Si atoms that deviates substantially from their static effective charges. We establish an accurate tunability of the vertical location of the p-p-σ and p-p-π bands and show that under compressive biaxial strain the density of states decreases, and conversely for tensile biaxial strain. This coupling between the tunability of strain-mediated density of states and semiconducting properties in a monolayered structure may allow for the development of applications in semiconducting stretchable electronics.