Role of effective tensile strain in electromechanical response of helical graphene nanoribbons with open and closed armchair edges

There is a growing need to understand the mechanical and electronic properties of nonideal graphene nanoribbons. Using objective molecular dynamics and a density-functional-based tight-binding model, we investigate the effects of torsion on the electromechanical properties of graphene nanoribbons with armchair edges. We propose to characterize with an effective tensile strain scalar the torsional mechanical response, including a reverse Poynting effect, and the fundamental band-gap modulations. The demonstrated utility of this concept in both the mechanical and electrical domains provides a perspective for understanding the electromechanical response in a unified way and for designing nanoelectromechanical devices with graphene components.