Adsorption by design: tuning atom-graphene van der Waals interactions via mechanical strain

TL;DR

This paper investigates how uniaxial strain on graphene modifies van der Waals interactions with various atoms, revealing potential for mechanically tuning adsorption properties and suppressing quantum reflection.

Contribution

It provides a detailed analysis of strain effects on atom-graphene van der Waals forces and introduces a method to estimate Lennard-Jones parameters under strain.

Findings

Strain significantly enhances van der Waals potential.

Quantum reflection can be suppressed by strain.

Strain shifts adsorption potential minima to higher distances.

Abstract

We aim to understand how the van der Waals force between neutral adatoms and a graphene layer is modified by uniaxial strain and electron correlation effects. A detailed analysis is presented for three atoms (He, H, and Na) and graphene strain ranging from weak to moderately strong. We show that the van der Waals potential can be significantly enhanced by strain, and present applications of our results to the problem of elastic scattering of atoms from graphene. In particular we find that quantum reflection can be significantly suppressed by strain, meaning that dissipative inelastic effects near the surface become of increased importance. Furthermore we introduce a method to independently estimate the Lennard-Jones parameters used in an effective model of He interacting with graphene, and determine how they depend on strain. At short distances, we find that strain tends to reduce the interaction strength by pushing the location of the adsorption potential minima to higher distances above the deformed graphene sheet. This opens up the exciting possibility of mechanically engineering an adsorption potential, with implications for the formation and observation of anisotropic low dimensional superfluid phases.