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Unformatted text preview: ntical. Solution of 3D Lattice Equation of Motion
Solution Phonon Dispersion in FCC with 2 Atom Basis
Phonon http://debian.mps.krakow.pl/phonon/Public/phrefer.html Approaches to Calculating Electronic Bandstructure
Bandstructure
Nearly Free Electron Approximation:
• Superposition of a few plane waves
Cellular Methods (Augmented Plane Wave):
• Plane wave between outside rs
• Atomic orbital inside rs (core)
Pseudopotential Approximation:
• Superposition of plane waves
coupled by pseudopotential
k.p:
• Superposition of bandedge (k=0) wavefunctions
Tightbinding Approximation (LCAO):
• Superposition of atomic orbitals Band Formation in 1D Solid
Band
Simple model for a solid: the onedimensional solid, which consists of a single, infinitely long
line of atoms, each one having one s orbital available for forming molecular orbitals (MOs). When the chain is extended:
The range of energies covered by the MOs
is spread
This range of energies is filled in with more
and more orbitals
The width of the range of energies of the
MOs is finite, while the number of molecular
orbitals is infinite: This...
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This document was uploaded on 03/19/2014 for the course EECS 6.730 at MIT.
 Spring '03
 TerryOrlando

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