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Ferromagnetic Semiconductor-Metal Transition in Heterostructures of Electron Doped Europium Monoxide

dc.contributor.advisorKroha, Johann
dc.contributor.authorStollenwerk, Tobias
dc.date.accessioned2020-04-18T23:58:02Z
dc.date.available2020-04-18T23:58:02Z
dc.date.issued17.10.2013
dc.identifier.urihttp://hdl.handle.net/20.500.11811/5757
dc.description.abstractIn the present work, we develop and solve a self-consistent theory for the description of the simultaneous ferromagnetic semiconductor-metal transition in electron doped Europium monoxide. We investigate two different types of electron doping, Gadolinium impurities and Oxygen vacancies. Besides the conduction band occupation, we can identify low lying spin fluctuations on magnetic impurities as the driving force behind the doping induced enhancement of the Curie temperature. Moreover, we predict the signatures of these magnetic impurities in the spectra of scanning tunneling microscope experiments. By extending the theory to allow for inhomogeneities in one spatial direction, we are able to investigate thin films and heterostructures of Gadolinium doped Europium monoxide. Here, we are able to reproduce the experimentally observed decrease of the Curie temperature with the film thickness. This behavior is attributed to missing coupling partners of the localized 4f moments as well as to an electron depletion at the surface which leads to a reduction of the number of itinerant electrons. By investigating the influence of a metallic substrate onto the phase transition in Gadolinium doped Europium monoxide, we find that the Curie temperature can be increased up to 20%. However, as we show, the underlying mechanism of metal-interface induced charge carrier accumulation is inextricably connected to a suppression of the semiconductor-metal transition.
dc.language.isoeng
dc.rightsIn Copyright
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectFerromagnetismus
dc.subjectHalbleiter
dc.subjectQuantenstörstellen
dc.subjectKondo-Effekt
dc.subjectRiesenmagnetowiderstand
dc.subjectFerromagnetism
dc.subjectSemiconductor
dc.subjectKondo effect
dc.subjectGiant magnetoresistance
dc.subject.ddc530 Physik
dc.titleFerromagnetic Semiconductor-Metal Transition in Heterostructures of Electron Doped Europium Monoxide
dc.typeDissertation oder Habilitation
dc.publisher.nameUniversitäts- und Landesbibliothek Bonn
dc.publisher.locationBonn
dc.rights.accessRightsopenAccess
dc.identifier.urnhttps://nbn-resolving.org/urn:nbn:de:hbz:5n-33364
ulbbn.pubtypeErstveröffentlichung
ulbbnediss.affiliation.nameRheinische Friedrich-Wilhelms-Universität Bonn
ulbbnediss.affiliation.locationBonn
ulbbnediss.thesis.levelDissertation
ulbbnediss.dissID3336
ulbbnediss.date.accepted2013-09-16
ulbbnediss.fakultaetMathematisch-Naturwissenschaftliche Fakultät
dc.contributor.coRefereeKollath, Corinna


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