Phonons versus Photons
Date: Spring 2012
In crystals we talk of phonons. How do phonons differ from photons? Are the phonon particles like photons having definite spin etc?
A photon is a particle or wave, a quantum of the electromagnetic field having both vibratory and particle properties. Photons have transverse waves that are perpendicular to its travel.
A phonon is a quantum of the vibrational degrees of freedom in a condensed crystal lattice. Phonons are collective vibrations, compressional energies contained within the particles of the lattice.
This is a helpful reference: 6.720J/3.43J - Integrated Microelectronic Devices - Fall 2002
As a side-note: the phonons you refer to are not the “phonons” as used in jargon of the music industry.
Peter E. Hughes, Ph,D.
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Update: June 2012