| dc.description.abstract | The pelaron problem has been of interest in condensed matter physics cind
held theory tor cibout half a century. Within the framework of Vcist variety of
theoreticcil approximations, the bulk polaron properties have been extensively
(explored and fairly well understood in the literature. In the last two deccides, with
the impressive progress achieved in the mici-ofabrication technology, it became
possible to ol)t£iin low dimensional microstructures, in which the charge ca.rriers
are confined in one or more spatial dii'ections. Consequently, there has appeared
(|uite a large interest in phonon coupling-induced effects and polaronic properties
of low dimensionally confined electrons.
In this context, this thesis work is devoted to the study of low dimensional
optical polaron properties, with the application of several different formal
approaches common in the literature, such as perturbation theory, variatioiicil
principles and Feynman path integral formalism. The model we adopt in this work consists of an electron, confined within an external potential (quantuni
well), and interacting via the Fröhlich Harniltonian with the bulk LO-phonons of
the relevant well material. Therefore, our primary concern is to give a clear view
of only the bulk phonon effects on an electron in confined media, and we disregard
all other complications that may come about from screening effects, phonon
confinement, etc. Under these assumptions, we calculate the ground state energy,
the effective mass, and some other quantities of polaron in several confinement
geometries. We also provide a broad interpolating overview to the one polaxon
problem in the overall range of electron-phonon coupling constant and in a general
type of confinement, which can be conformed from one geometriccd configuration
to another.
Another interesting theme of the polaron theory, magneto-polaron, is
considered in the context of the confinement effect on the polaron, brought about
by the rncignetic field. A detailed analysis is given in the case, where the effect
of electron-phonon coupling is dominated over by the magnetic field counterpart
of the problem. | en_US |
