# What is the physical meaning of the Thomas-Fermi vector?

1. Apr 6, 2015

### rwooduk

The Thomas-Fermi wavevector relates to the damping of an electric field caused by build up of carriers around an impurity (screening). But I cant understand it's physical meaning.

Wiki states "Thomas–Fermi screening is the limit of the Lindhard formula when the wavevector (the reciprocal of the length-scale of interest) is much smaller than the fermi wavevector, i.e. the long-distance limit."

So it applies when the wave vector is much smaller than the fermi wavevector, but I'm trying to visualise a physical meaning of what the Thomas-Fermi wavevector actually is.

Any ideas would really be appreciated.

2. Apr 11, 2015

### Greg Bernhardt

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?

3. Apr 11, 2015

### DrDu

I suppose with "wiki" you don't mean "wiki, the viking" but are refering to this entry in wikipedia:
http://en.wikipedia.org/wiki/Thomas–Fermi_screening
Did you check already the source cited, i.e. the book by Ashcroft and Mermin?
You probably would generate more answers if you wouldn't leave it to the readers to figure out what you may talk about.

Basically, $2\pi/k_0$ is the characteristic length over which a static perturbation is screened in a metal.

4. Apr 12, 2015

### rwooduk

Lol, I remember that show, ey, hey, Wickie hey, Wickie, hey!

Anyhow thanks for the tip, I managed to find a copy of the book and read the section on the wavevector and the following underlined parts I guess are physical interpretations, aside from these its mostly derivation.