Are there energy bands for alloys?

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Discussion Overview

The discussion revolves around the concept of Fermi energy in alloys, exploring whether a quantum mechanical approach can be applied to understand the conductivity properties of these materials. Participants consider the complexities involved in calculating Fermi levels in alloys compared to pure metals.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants assert that there is a Fermi level for alloys, but calculating it is more complex than for pure metals.
  • One participant inquires about the specific complexities involved and seeks hints towards relevant equations and principles, particularly in Fermi-Dirac statistics.
  • Another participant suggests looking up papers and mentions that calculating the Fermi surface of a metal typically requires numerical methods.
  • One participant expresses gratitude for the guidance and later clarifies that they were specifically looking for information on Fermi surfaces.
  • A participant acknowledges their limited knowledge in the field but offers a general background in Solid State physics.

Areas of Agreement / Disagreement

Participants generally agree that there is a Fermi level for alloys, but they express uncertainty regarding the complexity of its calculation. The discussion remains unresolved regarding specific methods or equations applicable to alloys.

Contextual Notes

The discussion highlights the limitations in available resources and knowledge regarding the calculation of Fermi energy levels in alloys, indicating a reliance on numerical methods and the need for further literature exploration.

Psinter
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In metals, there is a concept called the Fermi energy which you can calculate with the following:

Electron concentration in the solid:
<br /> n = (valency)*\frac{N_{A}D}{M_{AT}}\\<br />
Where:
n = electron concentration
valency = number of valency electrons in the atom
N_{A} = Avogadro constant
D = element density
M_{AT} = atomic mass

Energy of Fermi at absolute zero (0K):
E_{F0} = (\frac{h^2}{2m_e})(\frac{3n}{\pi})^{\frac{2}{3}}(\frac{1}{q})

Where:
E_{F0} = energy of Fermi at absolute zero (0K)
h = Plank's constant
m_e = effective electron mass at rest
n = electron concentration
\frac{1}{q} = reciprocal of electron charge (to convert energy units to electron volts)

However, the math above is for a single element. Is there any quantum mechanical approach for the same concept, but in alloys where you have a metallic bonding and the same crystalline structure?

I want to know if there is such a thing as Fermi energy in such structures (alloys) that can be tackled mathematically in a quantum mechanical way. Such that one could describe conductivity properties of an alloy. Or if there are other models for that.
 
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Yes, there is a Fermi level for alloys. It may not be so easy to calculate as in the simple model in your post.
Even for pure metals may be quite complicated actually.
 
nasu said:
Yes, there is a Fermi level for alloys. It may not be so easy to calculate as in the simple model in your post.
Even for pure metals may be quite complicated actually.
Hi,

Thanks for your answer.

How much more complex does it get? Any hints of what is it I'm after? A set of Equations and principles in the Fermi-Dirac statistics perhaps?

I've been reading a book which discusses those quantum mechanical principles in metals. So far so good, but I haven't found what I'm looking for which is in the end, finding Fermi energy levels of an alloy. That book discusses what happens with Fermi Energies in a metal to metal contact, but not an alloy.

I've already covered a wide range of principles, including the Fermi-Dirac statistics and other models with their equations and examples for specific elements. Still, I can't find what I'm looking for. Therefore my question: any hints?
 
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nasu said:
You can look up some papers. Calculating the Fermi surface of a metal is not trivial, as I said. Usually is done by numerical methods, I suppose.
From the hits below you can see that the concept is used for alloys. If you want to do your own calculations you may need to read some books.

https://www.google.ca/webhp?sourcei...spv=2&ie=UTF-8#q=Fermi+surface+ordered+alloys
Thank you very much :smile:.

Later edit: Fermi surfaces is what I was looking for. Thanks again.
 
Last edited:
You are welcome. Unfortunately I don't know details, I did not work in this field. I just have the general Solid State background.
 

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