Stdimtical Physics 267Fig. 2.20.Solution:
The density of states is
47rV ( 2m)3/2
h3D(E) =
(a) If T = 0, the total number of electrons is
2
3EF
N = l D(E)dE = -D(EF)EF.(c) At low temperatures 1.1 >> kT,= /,'D(E)dE + 7r2 -(kT)'D'(p) + -(kT)4D"'(p) 7T4 +...
6 3 60Fy 87~V(2rn)~/' 3h3 p3/2 [1+ f (?,"I ,