Condensed matter-integral over density of states

[ehrenfest]

condensed matter--integral over density of states

Homework Statement

http://online.physics.uiuc.edu/courses/phys460/fall06/handouts/460-lect12.pdf

Could someone explain to me why the first equation on slide 22 is true?

Homework Equations

The Attempt at a Solution

 

[malawi_glenn]

you mean:

Quantitative evaluation?

 

[ehrenfest]

you mean:

Quantitative evaluation?

What? I mean I don't understand why it is true. It is also on page 142 of Kittel.

 

[malawi_glenn]

What? I mean I don't understand why it is true. It is also on page 142 of Kittel.

Oki I just mean the eq under that headline.

any way here it goes:

take eq 24 on p 142. and read the 3lines above it.

What is the fermi dirac distribution at T = 0K? well f (T goes to 0) = 1.. (see eq 5 p.136 and take limit t goes to 0).

and you only have to integrate up to the fermi energy at 0K due to the density of state function. see fig 5 p.140.

 

[ehrenfest]

Oki I just mean the eq under that headline.
What is the fermi dirac distribution at T = 0K? well f (T goes to 0) = 1.. (see eq 5 p.136 and take limit t goes to 0).

f (T goes to 0) = 1 only if mu > epsilon

 

[malawi_glenn]

Oh yes, it meant when kT << E_f

:)

 

[ehrenfest]

Oh yes, it meant when kT << E_f

:)

Why does that imply that mu is greater than epsilon?

 

[ehrenfest]

Oki I just mean the eq under that headline.

Oh--yes it is the equation under that headline--sorry.

 

[ehrenfest]

see fig 5 p.140.

I see,the area of region 1 must be the same as the area of region 2.