5. Transport properties 5. Transport properties 5.2 Electrical - - PowerPoint PPT Presentation

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5. Transport properties 5. Transport properties 5.2 Electrical - - PowerPoint PPT Presentation

Oct 02, 2023 360 likes •403 views

5. Transport properties 5. Transport properties 5.2 Electrical conductivity 5. Transport properties 114 116 5.1. Semi-classical approximation Effective mass tensor Electron is a particle moving with group velocity: Wave-function changes

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SLIDE 1

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  • 5. Transport properties
  • 5. Transport properties

5.1. Semi-classical approximation

Electron is a particle moving with group velocity: Wave-function changes according to:

Bloch oszillation

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5.2 Electrical conductivity

  • 5. Transport properties

electrons holes

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5.2 Electrical conductivity

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Effective mass tensor

flat band ⇒ heavy electrons or holes dispersing band ⇒ light electrons or holes

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5.2 Boltzmann equation

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SLIDE 2

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5.2 Electrical conductivity

  • 5. Transport properties

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5.2 Electrical conductivity of metals

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5.2 Electrical conductivity of metals

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Temperature dependence (Matthiesen rule) At low temperatures:

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5.3. Thermal conductivity

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Wiedemann – Franz´sches Gesetz

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SLIDE 3

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5.4. Electrons in magnetic fields

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electron hole

  • pen orbit

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5.4. Electrons in magnetic fields

  • 5. Transport properties

condensation on Landau levels, Landau – cylinders B

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5.4. de Haas – van Alphen effect

  • 5. Transport properties

Oscillation of the magnetic susceptibility With external magnetic field

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5.5. E ⊥ B – Hall Effect

  • 5. Transport properties

Non-closed orbits or carriers with different mobility or concentration ⇒ RH depends on magnetic field B