Band engineering in graphene with superlattices of substitutional defects

TL;DR

This study demonstrates how graphene's electronic properties can be precisely tuned using superlattices of substitutional nitrogen and boron defects, enabling control over band gaps and carrier dynamics through symmetry and structural modifications.

Contribution

The paper introduces a method to engineer graphene's band structure via superlattices of substitutional defects, highlighting the role of symmetry and superlattice parameters in band modification.

Findings

Superlattice symmetry determines whether Dirac cones are preserved or a band gap opens.

Band parameters scale as 1/n^p, with p between 1 and 2, depending on the superlattice.

Graphene's electronic properties can be extensively tuned by adjusting superlattice parameters.

Abstract

We investigate graphene superlattices of nitrogen and boron substitutional defects and by using symmetry arguments and electronic structure calculations we show how such superlattices can be used to modify graphene band structure. Specifically, depending on the superlattice symmetry, the structures considered here can either preserve the Dirac cones (D_{6h} superlattices) or open a band gap (D_{3h}). Relevant band parameters (carriers effective masses, group velocities and gaps, when present) are found to depend on the superlattice constant n as 1/n^{p} where p is in the range 1-2, depending on the case considered. Overall, the results presented here show how one can tune the graphene band structure to a great extent by modifying few superlattice parameters.