The fate of the resonating valence bond in graphene

TL;DR

This paper uses advanced quantum Monte Carlo methods to analyze the resonating valence bond state in graphene, revealing its limited spatial extent and clarifying its role in chemical bonding.

Contribution

It introduces a variational wave function approach that improves ab initio calculations to study resonating valence bonds in realistic materials like graphene.

Findings

Identifies Kekulé and Dewar contributions to benzene bonds.

Quantifies the resonating valence bond energy (~0.01 eV/atom).

Shows the RVB picture in graphene is limited to a few atomic units.

Abstract

We apply a variational wave function capable of describing qualitatively and quantitatively the so called "resonating valence bond" in realistic materials, by improving standard ab initio calculations by means of quantum Monte Carlo methods. In this framework we clearly identify the Kekul\'e and Dewar contributions to the chemical bond of the benzene molecule, and we establish the corresponding resonating valence bond energy of these well known structures ($\simeq 0.01$eV/atom). We apply this method to unveil the nature of the chemical bond in undoped graphene and show that this picture remains only within a small "resonance length" of few atomic units.