A variational procedure is developed to study the properties of the bipolaron in the Fröhlich model including explicitly the electron band structure and taking into account the long-range repulsive electron-electron interaction. Adopting two different ansatze for the longitudinal optical phonon distribution function, the large-bipolaron and small-bipolaron limits are obtained. The evolution of the bipolaron ground state as a function of the electron-phonon coupling constant and of the bare-electronic bandwidth is discussed and the bipolaron phase diagram is presented. A clear crossover from the large-bipolaron to the small-bipolaron regime takes place.
Crossover from large to small bipolarons / Iadonisi, G.; Perroni, CARMINE ANTONIO; Cataudella, V.; De Filippis, G.. - In: JOURNAL OF PHYSICS. CONDENSED MATTER. - ISSN 0953-8984. - ELETTRONICO. - 13:(2001), pp. 1499-1515. [10.1088/0953-8984/13/7/312]
Crossover from large to small bipolarons
G. Iadonisi;PERRONI, CARMINE ANTONIO;G. De Filippis
2001
Abstract
A variational procedure is developed to study the properties of the bipolaron in the Fröhlich model including explicitly the electron band structure and taking into account the long-range repulsive electron-electron interaction. Adopting two different ansatze for the longitudinal optical phonon distribution function, the large-bipolaron and small-bipolaron limits are obtained. The evolution of the bipolaron ground state as a function of the electron-phonon coupling constant and of the bare-electronic bandwidth is discussed and the bipolaron phase diagram is presented. A clear crossover from the large-bipolaron to the small-bipolaron regime takes place.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
