Midgap states in corrugated graphene: Ab-initio calculations and effective field theory

TL;DR

This paper combines ab-initio calculations and effective field theory to study how rippling in graphene creates pseudomagnetic fields, leading to flat bands near the Fermi level, with implications for electronic properties.

Contribution

It introduces a combined computational and theoretical approach to analyze rippling effects on graphene's electronic structure, highlighting the impact of ripple relaxation on flat band formation.

Findings

Rippling induces pseudomagnetic fields affecting low-energy electronic states.

Flat bands near the Fermi level are formed as pseudo-Landau levels.

Annealing quenched ripples can eliminate flat bands.

Abstract

We investigate the electronic properties of corrugated graphene and show how rippling-induced pseudomagnetic fields alter graphene's low-energy electronic properties by combining first principles calculations with an effective field theory. The formation of flat bands near the Fermi level corresponding to pseudo-Landau levels is studied as a function of the rippling parameters. Quenched and relaxed ripples turn out to be fundamentally different is this respect: It is demonstrated, both numerically and analytically, that annealing of quenched ripples can destroy the flat bands.