Correlation between Charge Inhomogeneities and Structure in Graphene and Other Electronic Crystalline Membranes

TL;DR

This paper investigates how charge inhomogeneities influence the formation of ripples in graphene, revealing a coupling mechanism that explains experimental observations of charge puddles and structural ripples.

Contribution

It introduces a novel explanation linking charge fluctuations to structural ripples in graphene, highlighting the role of free electrons in membrane deformation.

Findings

Charge inhomogeneities correlate with ripple formation.

The mechanism reproduces experimental charge puddles.

Ripples are driven by charge-structure coupling in graphene.

Abstract

Only one atom thick and not inclined to lattice defects, graphene represents the ultimate crystalline membrane. However, its structure reveals unique features not found in other crystalline membranes, in particular the existence of ripples with wavelength of 100-300 Angstroms. Here, I trace the origin of this difference to the free electrons in the membrane. The deformation energy of the lattice creates a coupling between charge fluctuations and the structure, resulting in ripples on the membrane, correlated with charge inhomogeneities. In graphene this mechanism reproduces the experimental result for both charge puddles and ripples.