Ab initio strain engineering of graphene: opening bandgaps up to 1 eV

We employ electronic structure calculations based on Density Functional Theory (DFT) to strain engineer graphene's bandgap. Specifically, working in the finite deformation setting, we traverse the three-dimensional in-plane strain space to determine states capable of opening significant bandgaps in graphene. We find that biaxial strains comprising of tension in the zigzag direction and compression in the armchair direction are particularly effective at tuning graphene's electronic properties, with resulting bandgaps of up to 1 eV. Notably, we ascertain that a 11% strain in the zigzag direction in combination with -20% in the armchair direction produces a bandgap of approximately 1 eV. We also establish that uniaxial and isotropic biaxial strains of up to +/- 20% are incapable of opening bandgaps, while shear strains of +/- 20% can introduce bandgaps of around 0.4 eV.