Is the Work Function of Graphene Equal to the Binding Energy?

In summary, the work function of graphene is assumed to be 4.5 eV and is related to, but not equal to, the binding energy ##E_B## as given on Wikipedia. ##E − E_F## in the graph on the right represents the energy at a particular point in the Brillouin zone, which may not be the Fermi level. The point labeled K in the plot on the left is the second Brillouin zone K-point.
  • #1
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Homework Statement
See the attached image.
Relevant Equations
The theory section on ARPES on Wikipedia: https://en.wikipedia.org/wiki/Angle-resolved_photoemission_spectroscopy#Theory
Consider the attached screenshot. The work function of graphene is assumed to be 4.5 eV.

1. Does the work function correspond to the binding energy ##E_B## as given on Wikipedia? What is ##E## in ##E−E_F## in the graph on the right?
2. "...the Fermi level at the K-point..."; is this the point ##E=E_F## above K in the graph on the right?
3. "...the second Brillouin zone K-point..."; which point is this in the two pictures?
Screen Shot 2021-03-11 at 14.50.51.png
 
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  • #2
1. No, the work function does not correspond to the binding energy ##E_B## as given on Wikipedia. The work function is related to the binding energy, but is not equal to it. ##E## in ##E − E_F## in the graph on the right is the energy at a particular point in the Brillouin zone, which is not necessarily the Fermi level.2. Yes, this is the point ##E = E_F## above K in the graph on the right.3. The second Brillouin zone K-point is the point labeled K in the plot on the left.
 

FAQ: Is the Work Function of Graphene Equal to the Binding Energy?

What is ARPES and how does it work?

ARPES (Angle-Resolved Photoemission Spectroscopy) is a technique used to measure the electronic structure of a material. It works by shining a beam of photons onto the material's surface, causing electrons to be ejected. These electrons are then measured and their kinetic energy and emission angle are used to determine information about the material's electronic structure.

Why is graphene a popular material for ARPES calculations?

Graphene is a single layer of carbon atoms arranged in a hexagonal lattice. It is a highly conductive material with unique electronic properties, making it an ideal candidate for ARPES measurements. Additionally, its simple structure allows for accurate theoretical calculations to be compared with experimental data.

What are the main challenges in performing ARPES calculations on graphene?

One of the main challenges in ARPES calculations on graphene is accurately modeling the effects of the substrate on the electronic structure. The presence of the substrate can alter the electronic properties of graphene, making it difficult to compare theoretical calculations with experimental data. Additionally, graphene is a highly anisotropic material, meaning its properties vary depending on the direction of measurement, which can complicate data interpretation.

How do ARPES calculations on graphene contribute to our understanding of its electronic properties?

ARPES calculations on graphene provide valuable information about its electronic band structure, Fermi surface, and other electronic properties. By comparing experimental data with theoretical calculations, we can gain a deeper understanding of the behavior of electrons in graphene and how it differs from other materials. This information is crucial for developing new applications and technologies based on graphene.

What are some potential future developments in ARPES calculations on graphene?

As technology and techniques continue to advance, there are several potential developments in ARPES calculations on graphene. These include the ability to perform ARPES measurements on suspended graphene, which eliminates the effects of the substrate, and the development of new theoretical models that can accurately account for the anisotropic nature of graphene. Additionally, combining ARPES with other techniques, such as scanning probe microscopy, could provide even more detailed information about the electronic properties of graphene.

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