Waht are phonons?

[Mk]

Yeah, what are phonons? Has to do with heat I think... quantized vibrations in a rigid crystal lattice?... where do I find a quantum physics to English translation on bable fish? :biggrin:

[Astronuc]

Indeed phonons are related to the atomic lattice vibrations which are responsible for heat conduction and sound in a solid, or thermodynamically speaking, a phonon is a quantum of lattice vibrational energy in a crystal, but they can also apply to liquids.

Eric Weisstein's site simply states - A quasiparticle which is a quantized sound wave and which can occur in solids and liquid helium II.

A better description is found at - http://hyperphysics.phy-astr.gsu.edu/hbase/solids/phonon.html

In ceramic material, like UO2, phonon conduction is the predominant mode of heat conduction, and with phonon scattering, decreases as temperature increases. At some temperature however, something like 1600°C, electron conduction becomes predominant and the thermal conductivity actually increases.

Metals on the other hand generally show an increase in thermal conductivity with temperature.

On the other hand, consider pure acoustical or optical phonons -
http://www.chembio.uoguelph.ca/educmat/chm729/Phonons/cont.htm