The failure of the free electron theory of metals

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The discussion revolves around the failure of the free electron theory of metals, specifically questioning the limitations of the free electron model in explaining various physical phenomena related to electron behavior in metals.

Discussion Character

  • Conceptual clarification, Assumption checking, Exploratory

Approaches and Questions Raised

  • Participants explore reasons for the perceived failure of the free electron theory, with some referencing specific texts and discussing the interactions that electrons have with the lattice, each other, and impurities. Questions about the definitions and terminology related to the theory are also raised.

Discussion Status

The discussion is active, with participants providing insights and references to literature. Some have suggested looking into specific chapters of relevant texts for more detailed information, while others have pointed out the need for clarity on terminology. There is no explicit consensus on the failure of the theory, as some participants question the assertion itself.

Contextual Notes

Participants mention specific constraints such as the limitations of the free electron model and its inability to account for various phenomena, indicating a focus on theoretical understanding rather than practical solutions.

ziadett
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I was woundering?

why did the free electron theory of metals fail (the free electron model)?
 
Last edited:
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why did the free electron theory of metals fail "the free electron of model"
my effort:
Because it was unable to answer why the mean free path of electrons reaches 20nm in a good conducting metal "like silver" in room tempereture.
 
Last edited:
any answers
 
Who said it failed?
 
nbo10 said:
Who said it failed?

Ashcroft and Mermin did in the whole of Chapter 3 of their book "Solid State Physics".

Zz.
 
ziadett said:
why did the free electron theory of metals fail (the free electron model)?
The free electron model (as put forth by Drude, and modified by Sommerfeld and others) "failed" because for the most part, electrons aren't completely free. They interact with (i) the lattice, (ii) each other, and (iii) impurities. Drude incorporated (i) into his model in the form of a hard-sphere interaction, but completely neglected the other interactions. Sommerfeld made some corrections to this purely classical model, by ensuring that the electron gas obey Fermi statistics. This fixed some problems (like the overestimates of the electronic heat capacity), but still didn't cover for the missing interactions in the model.

The free electron model was understood to be an approximation, when it was proposed by Drude. The initial surprise was that it was far more successful than expected (eg: the Wiedemann-Franz Law), particularly in the case of the alkali and alkaline Earth elements.

Due to its limitations, the free electron model was unable to account for things like magnetoresistance, thermal dependence of conductivity, optical properties and the host of many body phenomena that result from electron-electron interactions being of importance.
 
Aren't the "free-electron theory" and the "free-electron model" the same thing?

You might try looking up the "nearly-free- electron model."
 
Look up chapter three in Ashcroft&Mermin, it just happens to be named "Failures of the Free Electron Model" and probably contains more than enough information for you.
 
  • #10
Thread merged.

ziadett : I strongly suggest you re-read the PF Guidelines that you have agreed to. There is a an explicit instruction that multiple posting is not allowed.

Zz.
 
  • #11
sorry man no more multiple posting from me any more
 

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