Polarization in graphene nanoribbons with inherent defects using first-principles calculations

Abstract

This study demonstrates the mechanism of strain-induced polarization in defective armchair graphene nanoribbons (AGNRs) using first-principles calculations. We estimate the piezoelectric coefficients of AGNR systems with different types of defects: line, divacancy, and Stone–Wales (SW) defects. At first, we compare the results of AGNRs having non-centrosymmetric pores subjected to an axial load with the existing results of graphene as well as graphitic carbon nitrides, and we confirm that the flexoelectric effect indeed comes into picture mechanistically when the symmetry of 2D systems breaks. Then, we carry out comprehensive first-principles calculations for AGNRs with various types of defects, which usually form during the synthesis of GNRs. The calculations were performed via the simulation software, real-space grid-based projector-augmented wave (GPAW), and a Python code based on the projector-augmented wave method for density functional theory (DFT). Our research reveals that polarization can be engineered in graphene by changing the pore/defect symmetry and concentration. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.