Initially, the carrier temperature decreases fast via emission of optical phonons.

This creates a non-equilibrium "over-population" of optical phonons and thus causes their increased reabsorption by the charge-carriers significantly suppressing any cooling.

The model developed in this paper is macroscopic and based on electrostatic coupling of an electron to polar optical phonons.

Phonons on the band that cross the origin are known as acoustic phonons, the others as optical phonons.

Non-polar optical phonons must generally be considered in covalent semiconductors and the L-valley of GaAs.

Scattering of electrons by optical phonons in carbon nanotube channels has two requirements:

The dominant scattering mechanism at room temperature is that of electrons emitting optical phonons.

However, optical phonons have a short life-time (they split into two due to anharmonicity) and therefore they add some important complications.

At high electric fields, drift velocity saturates due to scattering from optical phonons.

Indium phosphide also has one of the longest-lived optical phonons of any compound with the zincblende crystal structure.