Influence of Quadratic Interactions on Impurity Absorption Bands in Solids

✍ Scribed by G. F. Levenson

• Publisher: John Wiley and Sons
• Year: 1971
• Tongue: English
• Weight: 762 KB
• Volume: 43
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/pssb.2220430235

✦ Synopsis

Abstract

General integral relations are derived for the impurity absorption band in the case of arbitrarily strong both linear and quadratic electron‐phonon or electron‐magnon interaction, which are valid also in the presence of weak anharmonic relaxation of normal modes. These relations can be useful as a starting point for the approximate analytic treatment of impurity spectra in the cases when both linear and quadratic terms in the interaction Hamiltonian are important. In particular, the high‐temperature line shape of the absorption band is investigated. Expressions for the low‐temperature shape, bandwidth, and shift of the central line in the electron‐magnon spectra are derived, and formulae for the absorption spectrum of an impurity electron interacting with only one local mode are obtained.