Strain fields in graphene induced by nanopillars

The mechanical and electronic properties of a graphene membrane placed on top of a superlattice of nanopillars are investigated. We use molecular dynamics simulations to access the deformation fields and the tight-binding approaches to calculate the electronic properties. The system of interest consists of a triangular lattice of nanopillars with a period of a=750 nm over which the graphene layer is deposited. Ripples form in the graphene layer that span across the unit cell, connecting neighboring pillars, in agreement with recent experiments. We investigate the dependence of the pseudo-magnetic field (PMF) on unit cell parameters and the van der Waals interaction between graphene and the substrate. We find direct correspondence with typical experiments on pillars, showing intrinsic "slack" in the graphene membrane. PMF values are confirmed by the LDOS calculations at different positions of the unit cell showing pseudo-Landau levels at varying spacings. Our findings can be applied to other 2D materials (hBN, TMDs). Such systems are of interest as single-photon emitters where charge carriers are confined by the strain potential. Our study can be used as a guide to optimize parameters of the system for the improvement of the efficiency of the emitter.