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Fai L.C.,Mesoscopic and Multilayer Structure Laboratory | Fai L.C.,University of Yaounde I | Fomethe A.,Mesoscopic and Multilayer Structure Laboratory | Fomethe A.,University of Yaounde I | And 9 more authors.
Journal of Computational and Theoretical Nanoscience

A Feynman path integration approach is systematically applied to the polaron problem for the tubular geometry. The method represents a Gaussian approximation. The main quasi particle characteristics of the Fröhlich polaron, namely, the ground state energy and the effective mass are derived for two approaches. Numerical results are obtained with the all coupling limit. The results are found to imitate those of the spherical geometry modified by a logarithmic function. The polaron characteristics for the tubular geometry are found to be numerically greater than those of the spherical geometry. We observe that stronger and enhanced electron-phonon interaction can be achieved and consequently stronger coupling polaron only in tubular quantum dots with parabolic and rectangular confinement potentials. Copyright © 2010 American Scientific Publishers. All rights reserved. Source

Fai L.C.,Mesoscopic and Multilayer Structure Laboratory | Fomethe A.,Mesoscopic and Multilayer Structure Laboratory | Fomethe A.,University of Yaounde I | Mborong V.B.,Mesoscopic and Multilayer Structure Laboratory | And 7 more authors.
Superlattices and Microstructures

We investigate the effect of plasmon screening on the polaron characteristics following the Feynman variational method and find that the screening considerably reduces the polaron characteristics, as plasmon density increases. We establish that the factor contributing to this screening not only depends on the concentration, but also on the anisotropy of the dielectric permittivities, the temperature, and charge as well as on the layer width. The contribution of the surface effects to the total polaron characteristics are exceedingly small and can therefore be safely neglected. The characteristics are found to be strongly dependent on the screen function referred to as the F-function, and when screening parameters vanish this F-function vanishes and the polaron characteristics reduce to the familiar non-screen ones. The decrease of the polaron characteristics with an increase of the screening parameter is not exactly exponential but mimics that of a pseudoatom which has a much more slow decrease. © 2010 Elsevier Ltd. All rights reserved. Source

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