Carrierphonon

Carrierphonon, more commonly referred to as carrier-phonon interaction or electron-phonon interaction, denotes the coupling between itinerant charge carriers (electrons and holes) and quantized lattice vibrations (phonons) in a crystalline solid. This interaction is a primary mechanism for scattering and plays a central role in determining electronic transport and thermal properties of materials.

Microscopically, the interaction occurs through several channels. Deformation-potential coupling links electrons to acoustic phonons via changes in the crystal potential caused by lattice strains. In non-centrosymmetric or polar crystals, piezoelectric coupling and long-range Fröhlich coupling to polar optical phonons provide additional channels for scattering.

The strength and spectrum of carrier-phonon coupling are described by models and functions such as coupling constants and, in superconductivity, the Eliashberg function α^2F(ω). The standard theoretical treatment uses quantum many-body perturbation theory, with H_ep describing the interaction and scattering rates computed by Fermi’s golden rule.

Transport and thermal consequences include reduced carrier mobility and increased resistivity with rising temperature, as phonon populations grow. At low temperatures phonon scattering diminishes and impurity scattering dominates; at higher temperatures, optical phonons and polar interactions can become important, especially in polar semiconductors.

Carrier-phonon coupling underpins conventional superconductivity, where phonon exchange mediates electron pairing in many materials. It is also a key input in first-principles simulations of materials, informing transport coefficients and thermoelectric performance.