Silicene nanomeshes: bandgap opening by bond symmetry breaking and uniaxial strain

Abstract

Based on the first-principles calculations, we have investigated in detail the bandgap opening of silicene nanomeshes. Different to the mechanism of bandgap opening induced by the sublattice equivalence breaking, the method of degenerate perturbation through breaking the bond symmetry could split the π-like bands in the inversion symmetry preserved silicene nanomeshes, resulting into the πa1 − πa2 and πz1 − πz2 band sets with sizable energy intervals. Besides the bandgap opening in the nanomeshes with Dirac point being folded to Γ point, the split energy intervals are however apart away from Fermi level to leave the semimetal nature unchanged for the other nanomeshes with Dirac points located at opposite sides of Γ point as opposite pseudo spin wave valleys. A mass bandgap could be then opened at the aid of uniaxial strain to transfer the nanomesh to be semiconducting, whose width could be continuously enlarged until reaching its maximum Emax. Moreover, the Emax could also be tuned by controlling the defect density in silicene nanomeshes. These studies could contribute to the understanding of the bandgap engineering of silicene-based nanomaterials to call for further investigations on both theory and experiment.

Half-metallicity and ferromagnetism in penta-AlN2 nanostructure

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Equibiaxial Strained Oxygen Adsorption on Pristine Graphene, Nitrogen/Boron Doped Graphene, and Defected Graphene

“…The gap opens mainly because the sublattice symmetry is broken. The honeycomb sublattices (which are shifted by a translation vector [ 28 , 29 , 30 , 31 ]) sustain a displacement under strain. Based on the tight-binding method [ 32 ], the structure deformation would lead to the change of the corresponding transfer integral.…”

“…Based on the tight-binding method [ 32 ], the structure deformation would lead to the change of the corresponding transfer integral. Accordingly, there is the Π-like band splitting, which could open the gap, making the adsorption system turns into semiconductor material [ 31 , 33 , 34 ]. As a result, this indicates that the electronic transport properties of graphene adsorption systems can be effectively regulated by external forces.…”

Electronic and Magnetic Properties of Two-dimensional Nanomaterials beyond Graphene and Their Gas Sensing Applications: Silicene, Germanene, and Boron Carbide

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