Nano-engineered non-uniform strain in graphene

TL;DR

This paper investigates how nano-engineered non-uniform strain in graphene, induced by nano-pillars, can generate extremely high pseudo-magnetic fields and significantly alter local electronic properties, with implications for experimental verification.

Contribution

It introduces atomistic and tight-binding calculations to analyze strain-induced pseudo-magnetic fields and LDOS modifications in graphene on nano-pillars, enabling tailored pseudo-magnetic field profiles.

Findings

Pseudo-magnetic fields up to 5000 Tesla can be generated.

LDOS shows sub-lattice polarization at low energies.

Van Hove singularities shift at high energies.

Abstract

Recent experiments showed that non-uniform strain can be produced by depositing graphene over pillars. We employed atomistic calculations to study the non-uniform strain and the induced pseudo-magnetic field up to 5000 Tesla in graphene on top of nano-pillars. By decreasing the distance between the nano-pillars a complex distribution for the pseudo-magnetic field can be generated. Furthermore, we performed tight-binding calculations of the local density of states (LDOS) by using the relaxed graphene configuration obtained from the atomistic calculations. We find that the quasiparticle LDOS are strongly modified near the pillars, both at low energies showing sub-lattice polarization, and at high energies showing shifts of the van Hove singularity. Our study shows that changing the specific pattern of the nano-pillars allows us to create a desired shape of the pseudo-magnetic field profile while the LDOS maps provide an input for experimental verifications by scanning tunneling microscopy.