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Phys 460 Lecture 26

( pdf version - 6 slides/page )
Mon, December 4, 2006
Lecturer: Richard Martin 		No new homework today

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More on Nanostructures
Outline

  1. From previous lectures:
    • Part I: Crystal Structures, Diffraction, Reciprocal Lattice, Crystal binding
      Phonons, Dispersion curves, Thermal properties
    • Part II: Free electron gas, Energy bands for electrons in crystals Ekn, gaps, metals vs. insulators, semiconductors
    • Part III:
      • Semiconductor devices - inhomogeneous semiconductors - heterostructures
      • Semiconductor nanostructures
      • Metals - brief overview - electron gas ideas generalized to real metals
      • Superconductivity
      • Magnetism
      • Surfaces - tunneling - STM
  2. Previous motes on nanostructures - Lect 21, 25
    • Created by Applied Voltages
      Patterned metal gates on semiconductors
      Create “dots” that confine electrons
    • Created by material structures
      Clusters of atoms, e.g., Si29H36, CdSe clusters
      Buckyballs, nanotubes, . . .
  3. Created by phases of matter - new material today
    • Sensitive to size effects
    • Length scales set by the nature of the phase
    • Magnets – length scale ~ magnetic domain
      Control of domains, hysterisis by size of cluster
    • Superconductors – length scales ~ penetration depth – coherence length
      Can vary from nm to 1000's of nm - See examples in notes
Email clarification questions and corrections to rmartin@uiuc.edu
Email questions on solving problems to xin2@.uiuc.edu