Question

9(E) = 8VZtem3/2 1. (20 points) The Fermi energy in copper is 7.04 eV. a) What percentage of free electrons in copper are in the excited state at room temperature, 25°C? b) What percentage of free electrons in copper are in the excited state at the melting point of copper, 1083°C? The density of energy states per unit volume per unit energy interval in copper is given by 8V2m3/2 ZVĒ. h3VE, Note the m is the mass of an electron and h is h not h with a bar. The Fermi energy of a metal is h2 (3n 2/3 ềf = 2m (81) where n is the number density of available electrons (one for every atom) per unit volume. Note that you will get a Fermi energy of 7.04 eV. This is what I have given you. This is the lowest occupied level and thus this should be the lower limit on your integral. Use this Fermi energy for the Fermi level for both temperatures and ignore the small changes in density with temperature.

Answer 1

KeT 3@xio-23 T('k) ev 610IX 9.1 cat T 95'k2 2 73+ 25 290k A T=1093e - l083f 273 = 1356 K ev 1169.55 X10y en o.It&955 ev < < EF ET2 Femi- ira otu pohan fucter F(E,T) E-EFT + tos E = o (fere lew \ Flo,T)= EFIKBT +1 1- Ep +) 2- fF kBT EFEF kB7 EF At T- T KBT 257.025x10 e flo,T) = 0.00365 en 7104 = 0.365 T T2 Ad 0.116955 ex fro,T)= -0.0100 7.04 ev 61.93-1