Structural and Electronic Properties of Graphene and Silicene: An FP-(L)APW+lo Study

TL;DR

This study uses first-principles calculations to analyze the structural and electronic properties of graphene and silicene, revealing a buckled structure in silicene and confirming its electronic similarity to graphene.

Contribution

The paper provides new first-principles results on the lower bounds of lattice constants for graphene and silicene using the FP-(L)APW+lo method.

Findings

Silicene has a buckled structure with a buckling parameter of 0.44 Å.

Silicene's electronic structure is similar to graphene despite buckling.

New lower bounds for lattice constants of graphene and silicene are reported.

Abstract

We report here the structural and electronic properties of graphene and silicene (silicon analogue of graphene) investigated using first-principles calculations of their ground state energies employing full-potential (linearized) augmented plane wave plus local orbital (FP-(L)APW+lo) method. On structure optimization, we found that the graphene-like honeycomb structure of Si is buckled (buckling parameter $\Delta = 0.44$ \AA in constrast with graphene whose structure is planar ($\Delta = 0.0$ \AA). In spite of the buckled-structure, silicene has an electronic structure similar to that of graphene. The results are in agreement with previous reports based on other methods. We have also calculated the lower bounds of the lattice constant $"a"$ of these 2D systems, within the present method of study which are our new results.