Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: free electron theory

Learn more physics!

Most recent answer: 05/16/2013
Q:
What is the free electron theory?
- Daniek (age 16)
U.K
A:

I think you mean the free electron theory of electrons in conducting solids.

For background, you need to know something a little surprising, that electrons and other particles behave like waves, rather than like little points which are located at particular places. The conduction electrons in conductors are ones which have waves that spread out over many atoms. For these electrons, the background of atoms doesn't act like a set of little dots to bounce off of, but rather like a uniform medium, sort of like glass acts for light. These electrons, in some materials, behave almost as if they were in no medium whatsoever, i.e. as if they were free. Usually, however, there is at least one subtle effect of traveling in the solid, which is that the electrons act as if their mass were different than purely free electrons. That's a little bit like the way light travels freely through glass or water, etc., but not quite at the same speed as it travels through a vacuum.

Mike W.


(published on 10/22/2007)

Follow-Up #1: free electron theory

Q:
I want to know more about free electron theory
- alfred (age 18)
kannur Kerala
A:

We can steer you to some more in-depth sources. There's a brief Wikipedia article which has links to more detailed discussions. You might also look in any standard text on solid-state physics, e.g. Kittel's or Ashcroft and Mermin's.

Mike W.


(published on 05/16/2013)

Follow-up on this answer.