Class notes Applications of quantum mechanics-Solid state

UNIT-2 PHYSICS
Applications of Quantum Mechanics -

Solid state




Shreya Prasad

, SUMMARY

→ Classical theory ? Relaxation time
2
thermal velocity
=3km Drift velocity Vd=el
/




heard
R=
F- nerd J=rE
F-
S=£
↳ Mattheis entente :
f- fiefm metal G- R
{
_ -




) (
net impurity

→
Quantum theory :



KTF E Mtr
k¥p
k=nI
=

Ep Neff net
- __



a
Tomar
probability f-④
eE-Er!lk
=




factor
available
States
n =



¥§mµa "rE
'VE
stale

density
g = Efg)ˢ
Energy density NCE )=gE ) f- (E)-




n-t%E3dtfumivdou.ly
Nooffneeé

VF=j2EmI
Effective
f%¥yE_ =§Ef
→
man
Ewg=

h-2ci-E.im?-.)--EE.:.7E-oueD
M =




lorenz
1--4--2=-1,1%5
no He Ho
4- ¥ ) ]
-

. -




?⃝

, CLASSICAL ELECTRON THEORY
→ thermal
velocity
=


21mi =

3- KI ( %)
ruax-H-mier-fskm.TT I µ conductivity
nerd
velocity Vd=eE÷ I=neAVd
→ J= E-
Drift F- r
:




classical election
considered
theory
Mobility µ=eIm ¥
→ : =
manual
Boltzmann
theory
↳ Resistivity
:




^




✓
8=10 at T -0k Residual I is present
%
.




9=9,1 Pres



(
-
5- E-
g
r ,

Residual s E
S S E-
ne¥
T→ = - =




impunity
.




g- nerd




Ym
m m
!
=




net net nets litres impurities)
§ is dueto


&
'

I Eres II
=




B-
* CEFT DRAWBACKS :




1. Temperature dependence of S :
C- Vs s)




=÷a
f =
M "
not
s=
mn֖
S m
]3kyB
=




helps
3kBh =




need
safe


But in 8×7
reality
i.
,