On the stability of Fröhlich bipolarons in spherical quantum dots
Author
Senger, R. T.
Erçelebi, A.
Date
2002Source Title
Journal of Physics Condensed Matter
Print ISSN
0953-8984
Publisher
Institute of Physics
Volume
14
Issue
22
Pages
5549 - 5560
Language
English
Type
ArticleItem Usage Stats
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Abstract
In the strong-electron-phonon-coupling regime, we retrieve the stability criterion for bipolaron formation in a spherical quantum dot. The model that we use consists of a pair of electrons immersed in a reservoir of bulk LO phonons and confined within an isotropic parabolic potential box. In this particular quasi-zero-dimensional geometry, where the electrons do not have any free spatial direction to expand indefinitely, a plausible approach would be to treat the electrons either to form a bipolaronic bound state or enter a state of two close, but individual polarons inside the same dot. The confined two-polaron model adopted here involves the polaron-polaron separation introduced as an adjustable parameter to be determined variationally. It is found that the fundamental effect of imposing such a variational flexibility is to modify the phase diagram to a considerable extent and to sustain the bipolaron phase in a broader domain of stability.
Keywords
CalculationsElectrons
High temperature superconductors
Phase diagrams
Phonons
Semiconductor quantum dots
Stability
Electron-phonon coupling
Polarons