Mapping unoccupied electronic states of freestanding graphene by angle-resolved low-energy electron transmission

Wicki, Flavio; Longchamp, Jean-Nicolas; Latychevskaia, Tatiana; Escher, Conrad; Fink, Hans‐Werner

doi:10.1103/physrevb.94.075424

Cited by 24 publications

(17 citation statements)

References 31 publications

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“…I.e., all electrons are elastically back-reflected as the sample electronic band structure has no states that would allow the electrons to propagate within the solid. One can 'probe' the band structure of the solid above the vacuum level by measuring electron reflectivity as a function of energy and momentum [13][14][15]. Figure 1(b) shows the results of such an Angle-Resolved Reflected Electron Spectroscopy (ARRES) experiment on bulk graphite reproduced from Ref.…”

Section: Introductionmentioning

confidence: 99%

Nonuniversal Transverse Electron Mean Free Path through Few-layer Graphene

et al. 2019

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In contrast to the in-plane transport electron mean-free path in graphene, the transverse meanfree path has received little attention and is often assumed to follow the 'universal' mean-free path (MFP) curve broadly adopted in surface and interface science. Here we directly measure transverse electron scattering through graphene from 0 to 25 eV above the vacuum level both in reflection using Low Energy Electron Microscopy and in transmission using electron-Volt Transmission Electron Microscopy. From this data, we obtain quantitative MFPs for both elastic and inelastic scattering. Even at the lowest energies, the total MFP is just a few graphene layers and the elastic MFP oscillates with graphene layer number, both refuting the 'universal' curve. A full theoretical calculation taking the graphene band structure into consideration agrees well with experiment, while the key experimental results are reproduced even by a simple optical toy model.

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Section: Introductionmentioning

confidence: 99%

Nonuniversal Transverse Electron Mean Free Path through Few-layer Graphene

et al. 2019

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“…The non‐TBM bands of our interest are plotted with long‐dashed (red) and short‐dashed (blue) lines. The upper bands merge into scattering resonances of graphene , which is schematically shown with dashed (black) endings of lines.…”

Section: Introductionmentioning

confidence: 99%

Electronic structure of graphene: (Nearly) free electron bands versus tight‐binding bands

Kogan

Silkin

2017

Physica Status Solidi (b)

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In our previous paper [Phys. Rev. B 89, 165430 (2014)] we have found that in graphene, in distinction to the four occupied bands, which can be described by the simple tight‐binding model (TBM) with four atomic orbitals per atom, the two lowest lying at the Γ‐point unoccupied bands (one of them of a σ type and the other of a π type) can not be described by such model. In the present work, we suggest a minimalistic model for these two bands, based on (nearly) free electron model (FEM), which correctly describes the symmetry of these bands, their dispersion law and their localization with respect to the graphene plane.

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“…I.e., all electrons are elastically back-reflected as the sample electronic band structure has no states that would allow the electrons to propagate within the solid. One can probe the band structure of the solid above the vacuum level by measuring electron reflectivity as a function of energy and momentum [13][14][15]. Reflectivity is plotted as function of energy and in-plane momentum k k .…”

mentioning

confidence: 99%

Questioning a Universal Law for Electron Attenuation

Werner

2019

Physics

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In contrast to the in-plane transport electron mean-free path in graphene, the transverse mean-free path has received little attention and is often assumed to follow the "universal" mean-free path (MFP) curve broadly adopted in surface and interface science. Here we directly measure transverse electron scattering through graphene from 0 to 25 eVabove the vacuum level both in reflection using low energy electron microscopy and in transmission using electronvolt transmission electron microscopy. From these data, we obtain quantitative MFPs for both elastic and inelastic scattering. Even at the lowest energies, the total MFP is just a few graphene layers and the elastic MFP oscillates with graphene layer number, both refuting the universal curve. A full theoretical calculation taking the graphene band structure into consideration agrees well with experiment, while the key experimental results are reproduced even by a simple optical toy model.

show abstract

Mapping unoccupied electronic states of freestanding graphene by angle-resolved low-energy electron transmission

Cited by 24 publications

References 31 publications

Nonuniversal Transverse Electron Mean Free Path through Few-layer Graphene

Nonuniversal Transverse Electron Mean Free Path through Few-layer Graphene

Electronic structure of graphene: (Nearly) free electron bands versus tight‐binding bands

Questioning a Universal Law for Electron Attenuation

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