Interaction of strongly correlated electrons and acoustical phonons

• Veröffentlicht in: Физика низких температур
• Datum: 2006
• Hauptverfasser: Moskalenko, V.A., Entel, P., Digor, D.F.
• Format: Artikel
• Sprache: Englisch
• Veröffentlicht: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2006
• Schlagworte: Strong Correlations
• Online Zugang: https://nasplib.isofts.kiev.ua/handle/123456789/120196
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Zitieren: Interaction of strongly correlated electrons and acoustical phonons / V.A. Moskalenko, P. Entel, D.F. Digor // Физика низких температур. — 2006. — Т. 32, № 4-5. — С. 609–633. — Бібліогр.: 34 назв. — англ.

We investigate the interaction of correlated electrons with acoustical phonons using the extended Hubbard–Holstein model. The Lang–Firsov canonical transformation allows one to obtain mobile polarons for which a new diagram technique and generalized Wick’s theorem is used. The physics of emission and absorption of the collective phonon-field mode by the polarons is discussed in detail. In the strong-coupling limit of the electron-phonon interaction, and in the normal as well as in the superconducting phase, chronological thermodynamical averages of products of acoustical phonon-cloud operators can be expressed by the products of one-cloud operator averages. While the normal one-cloud propagator has the form of a Lorentzian, the anomalous one is of Gaussian form and considerably smaller. We have established the Mott–Hubbard and superconducting phase transitions in this model.