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Bipolaron stability in an ellipsoidal potential well
Author(s) -
Pokatilov E. P.,
Croitoru M. D.,
Fomin V. M.,
Devreese J. T.
Publication year - 2003
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200301785
Subject(s) - bipolaron , condensed matter physics , quasiparticle , ellipsoid , binding energy , radius , physics , feynman diagram , adiabatic process , phonon , quantum dot , polaron , quantum mechanics , electron , superconductivity , computer security , astronomy , computer science
Bipolaron states in ellipsoidal quantum dots are examined within the framework of Feynman's path‐integral formalism. The following characteristics of these quasiparticles are calculated: the binding energy, the number of phonons in the bipolaron cloud and the radii. The impact of both shape and size of a mesoscopic structure on the bipolaron characteristics is studied. It is shown, that in the case of strong confinement the influence of the confinement geometry is very pronounced. Two different cases are possible. (i) When the radius R k corresponding to a given k ‐axis of the ellipsoidal potential well is fixed to be less than the radius R 0 , at which the bipolaron binding energy in a spherical quantum dot achieves its maximum, the bipolaron binding energy passes consecutively through a local maximum and a local minimum with increasing the confinement strength corresponding to the other axes ( i ≠ k ). (ii) When R k ≫ R 0 , the bipolaron binding energy shows only a monotonous growth with decreasing the effective sizes of the structure along the other axes ( i ≠ k ).