polaronic

The term "polaronic" refers to a quasiparticle that arises when an electron or hole interacts strongly with the surrounding lattice of a crystal, particularly in ionic or polar materials. This interaction causes a distortion of the crystal lattice around the charge carrier, effectively creating a cloud of phonons (quantized lattice vibrations) that moves with the electron or hole. This combined entity – the electron or hole plus its associated lattice distortion – is known as a polaron.

Polaronic behavior is significant in various condensed matter systems, influencing their electrical and optical properties. The effective mass of the charge carrier is increased due to the inertia of the surrounding lattice distortion, which can lead to reduced mobility compared to a free electron. The strength of the electron-phonon coupling determines whether a charge carrier is considered a small polaron (localized and strongly coupled) or a large polaron (less localized and weakly coupled). Small polarons often exhibit hopping transport, while large polarons tend to move more like conventional charge carriers, albeit with a modified effective mass. The concept of the polaron is crucial for understanding phenomena such as electrical conductivity in semiconductors and insulators, as well as superconductivity in certain materials.