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Multiband Models for Colossal Magnetoresistance Materials and Diluted Magnetic Semiconductors

Title: Multiband Models for Colossal Magnetoresistance Materials and Diluted Magnetic Semiconductors.
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Name(s): Popescu, Florentin, author
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
Type of Resource: text
Genre: Text
Issuance: monographic
Date Issued: 2007
Publisher: Florida State University
Place of Publication: Tallahassee, Florida
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: 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.
Identifier: FSU_migr_etd-0478 (IID)
Submitted Note: A Dissertation submitted to the Department of Physics in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
Degree Awarded: Degree Awarded: Summer Semester, 2007.
Date of Defense: Date of Defense: May 30, 2007.
Keywords: Coulomb Attraction by Magnetic Impurities, Ferromagnetic Transition Temperature, Colossal Magnetoresistance, Diluted Magnetic Semiconductors, Dynamical Mean-Field Theory
Bibliography Note: Includes bibliographical references.
Advisory committee: 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.
Subject(s): Physics
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_migr_etd-0478
Host Institution: FSU

Choose the citation style.
Popescu, F. (2007). Multiband Models for Colossal Magnetoresistance Materials and Diluted Magnetic Semiconductors. Retrieved from http://purl.flvc.org/fsu/fd/FSU_migr_etd-0478