Several multiband models for Colossal Manetoresistance Materials and Diluted Magnetic Semiconductors are investigated within Dynamical Mean-Field Theory. The theoretical analysis of such models uses extensively the parametrization method for the bare Green's function to study the critical transition temperatures in a wide range of model's parameters; hoping amplitudes, couplings, and carrier concentrations. For both classes of materials, it is found within a two-band model that the transition temperature can be twice larger than the one predicted by the one band models and that its maximum is reached at a twice larger carrier concentration. It is also revealed that the off-diagonal hoppings, when considered, lead to a substantial boost of the ferromagnetic transition temperature. By accounting for the attractive Coulomb potential by acceptors in diluted magnetic semiconductors, the impurity to valence band crossover is studied as a function of doping and the critical values of doping, at which the crossover occurs, are estimated for various diluted magnetic semiconductors. / A Dissertation submitted to the Department of Physics in partial fulfillment of the
requirements for the degree of Doctor of Philosophy. / Degree Awarded: Summer Semester, 2007. / Date of Defense: May 30, 2007. / Coulomb Attraction by Magnetic Impurities, Ferromagnetic Transition Temperature, Colossal Magnetoresistance, Diluted Magnetic Semiconductors, Dynamical Mean-Field Theory / Includes bibliographical references. / Professor N. Bonesteel, Professor Directing Dissertation; Professor N. Dalal, Outside Committee Member; Professor P. Xiong, Committee Member; Professor J. Piekarewicz, Committee Member; Professor I. Chiorescu, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_168613 |
| Contributors | Popescu, Florentin (authoraut), Bonesteel, Professor N. (professor directing dissertation), Dalal, Professor N. (outside committee member), Xiong, Professor P. (committee member), Piekarewicz, Professor J. (committee member), Chiorescu, Professor I. (committee member), Department of Physics (degree granting department), Florida State University (degree granting institution) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource, computer, application/pdf |
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