The continuum theory of delocalized and self-trapped polarons and bipolarons in solids

• Published in: Physica. C, Superconductivity Superconductivity, 1995-01, Vol.254 (3), p.311-317
• Main Authors: Dzhumanov, S., Baimatov, P.J., Baratov, A.A., Khabibullaev, P.K.
• Format: Article
• Language: English
• Subjects: Binding energy; Continuum mechanics; Crystal lattices; High temperature superconductors; Numerical methods; Superconducting transition temperature; Superconductivity
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/0921-4534(95)00446-7

The continuum theory of delocalized (D) and self-trapped (S) polarons and bipolarons is developed within the adiabatic approximation and the direct variational approach. The role of each taken separately and the combined effects of the short- and long-range electron-lattice interactions as well as election correlations in the formation of D- and S-polarons and bipolarons is considered in detail. It is shown that the simultaneous accounting of these effects leads to increasing the ratio of the binding energy of a D-bipolaron to double the energy of a D-polaron to 0.372 at ε ∞/ ε 0 → 0 and to a noticeable expansion of the existence regions ( ε ∞/ ε 0 ⩽ 0.16) of these bipolarons. Numerical results show that the short-range electron-lattice interaction and electron correlation also play an important role in the formation of the S-bipolarons. The possible relations of the D- and S-bipolarons to superconductivity in high-temperature and other superconductors are considered.