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Unformatted text preview: ↑ Peltier coefficien
Heating and cooling of junctions, respectively, by (ΠA - ΠB)j if el.
Volta voltage: eV K = Φ 1 − Φ 2 = E F2 − E F1 λE
Wiederman-Franz law: σ = LT ,
2 L = 2.45 × 10-8 WΩK-2 Summary n-semiconductor (p-semiconductor analogous) S- 3
2 Summary S- 4
2 Summary σ = e(nµn + pµp) n(T): strong exponential dependence µ(T): weak dependence, only matters in
µ∝ T-3/2 scattering by phonons µ∝ T3/2 scattering by charged impurities Cf. metals:
n(T) = const. σ(T) ∝ µ(T) Conduction electrons in
Lorentz force ⇒ • Orbit on surfaces E(k) = const.
Metals: Fermi surfaces
Semiconductors: surfaces E(k) = const near
minimum of conduction band or maximum
of valence band.
• Orbits ⊥ B
Orbital frequency: ωc = e
mc h 3 dA
, cyclotron mass,
2 mc = m for free el. Summary Cyclotron resonance in HF field for ω = ωc ⇒ meff
Landau levels: condensation of electrons on ″Landau tubes″
(1-dim. electron gas || B)
ωc ∝ B ⇒ oscillations of
D(EF) with B 1
h2 2 E = const + n + hω c +
2m 4243 1 3
B = (0, 0, Bz) ⇒
in z − direction Hall effect
Electrons and holes experience same Lorentz force
⇒ for n = p only Hall voltage if µn ≠ µp 1
RH = − ,
ne S- 6
2 Summary 1
RH = −
Orbital momentum of electrons ⇒ magneti...
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This note was uploaded on 01/19/2010 for the course MATERIALS M504 taught by Professor Adelung during the Spring '02 term at Uni Kiel.
- Spring '02