Inelastic Effects in Low-Energy Electron Reflectivity of Two-dimensional Materials

TL;DR

This paper introduces a straightforward method to incorporate inelastic effects into low-energy electron reflectivity spectra calculations for 2D materials, enhancing the accuracy of theoretical predictions.

Contribution

It presents a novel approach to include inelastic effects in LEER spectra computations using a decay model with an imaginary potential term.

Findings

Accurate LEER spectra for multilayer graphene

LEER spectra for graphene on copper substrates

LEER spectra for h-BN on cobalt substrates

Abstract

A simple method is proposed for inclusion of inelastic effects (electron absorption) in computations of low-energy electron reflectivity (LEER) spectra. The theoretical spectra are formulated by matching of electron wavefunctions obtained from first-principles computations in a repeated vacuum-slab-vacuum geometry. Inelastic effects are included by allowing these states to decay in time in accordance with an imaginary term in the potential of the slab, and by mixing of the slab states in accordance with the same type of distribution as occurs in a free-electron model. LEER spectra are computed for various two-dimensional materials, including free-standing multilayer graphene, graphene on copper substrates, and hexagonal boron nitride (h-BN) on cobalt substrates.