[HexagonReversal]

>I am also wondering if the Fermi energy calculation using a slab is appropriate. The Fermi energy of a bulk crystal should be different from the one that is 3-atom-layer-thin, right? Will that render our calculated surface energy useless?

I figured out this question myself now. The work function is a surface property, not a bulk property. So that justifies the use of a slab for the Fermi energy calculation. But according to Wikipedia:

“The work function refers to removal of an electron to a position that is far enough from the surface (many nm) that the force between the electron and its image charge in the surface can be neglected.”

This will certainly introduce some error with our very thin slab, right? Wouldn’t it better if we calculate the Fermi energy with a full crystal instead?

• This reply was modified 2 years, 4 months ago by HexagonReversal.

[HexagonReversal]

One last question: is the Fermi energy, like the total energy, depends strongly on the choice of pseudo-potential and reference energy, such that it cannot be directly compared when a different pseudo-potential is used?

[HexagonReversal]

Correction: it is not the “surface energy” exercise, but the “work function” calculation exercise. This one: https://compmatphys.org/wp-content/uploads/2022/09/work-function.pdf

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