Electronic and Magnetic Properties of the Fe/GaAs(110) Interface

Iffländer, Tim

dc.contributor.advisor	Ulbrich, Rainer G. Prof. Dr.
dc.contributor.author	Iffländer, Tim
dc.date.accessioned	2016-02-29T09:46:23Z
dc.date.available	2016-02-29T09:46:23Z
dc.date.issued	2016-02-29
dc.identifier.uri	http://hdl.handle.net/11858/00-1735-0000-0028-86DE-A
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-5503
dc.language.iso	eng	de
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject.ddc	530	de
dc.title	Electronic and Magnetic Properties of the Fe/GaAs(110) Interface	de
dc.type	doctoralThesis	de
dc.contributor.referee	Ulbrich, Rainer G. Prof. Dr.
dc.date.examination	2015-10-30
dc.subject.gok	Physik (PPN621336750)	de
dc.description.abstracteng	Metal-semiconductor interfaces are present in every semiconductor device and are therefore of fundamental importance in modern technology. In this thesis we investigate the structural, electronic, and magnetic properties of the low-temperature (LT) grown Fe/GaAs{110} interface. In order to check the validity of theoretical models describing the microscopic process of Schottky barrier formation, the LT grown Fe/GaAs{110} interface serves as an ideal model system that is studied by means of atomically resolved cross-sectional scanning tunneling microscopy (XSTM) and spectroscopy (XSTS). Highly resolved LT XSTS measurements show a continuum of states inside the band gap of the p-type semiconductor. That these states are metal-induced gap states (MIGS) is demonstrated in a control experiment across a p-type GaAs edge without Fe film where no gap states are observed. Furthermore, we combine XSTS along the space charge region of the semiconductor with three-dimensional finite element simulations of the electrostatic potential inside the space charge region. In this way we take into consideration the tip-induced band bending, determine the Schottky barrier (SB) height of the ideal p-type Fe/GaAs(110) interface, and obtain a spatial and energetic map of the local density of states inside the valence band of the same interface. A comparison of the XSTS data and density functional theory (DFT) calculations reveals the relevance of both MIGS and bond polarization models. Moreover, the very good agreement between the XSTS and DFT data demonstrates that the XSTS technique is an excellent approach to investigate the microscopic process of SB formation. In this thesis, we also investigate the influence of different growth conditions on the structure, the SB height, and the charge distribution at p-type interfaces by means of XSTM and XSTS. Furthermore, in this thesis, the magnetic anisotropy of ultrathin (2—3 monolayer thin) LT grown Fe films on the GaAs{110} surface is investigated by means of in situ magneto-optic Kerr effect measurements in longitudinal, polar, transverse and mixed geometry. These measurements exhibit an out-of-plane magnetization which is unidirectionally coupled to the in-plane magnetization component along the <001> direction and directly related to the inversion asymmetry of the GaAs{110} surface in the same direction. Magneto-optic simulations show that this magnetic anisotropy cannot be explained by a simple canted magnetization of the Fe film.	de
dc.contributor.coReferee	Hofsäss, Hans Christian Prof. Dr.
dc.subject.eng	cross-sectional scanning tunneling microscopy	de
dc.subject.eng	cross-sectional scanning tunneling spectroscopy	de
dc.subject.eng	STM	de
dc.subject.eng	STS	de
dc.subject.eng	ideal metal-semiconductor interface	de
dc.subject.eng	Schottky barrier	de
dc.subject.eng	metal-induced gap states	de
dc.subject.eng	bond polarization	de
dc.subject.eng	in situ magneto-optic Kerr effect	de
dc.subject.eng	MOKE	de
dc.subject.eng	ultrathin magnetic films	de
dc.subject.eng	magnetic anisotropy of thin films	de
dc.subject.eng	Fe	de
dc.subject.eng	GaAs(110)	de
dc.subject.eng	tip-induced band bending	de
dc.subject.eng	3D finite element simulation	de
dc.subject.eng	space charge region	de
dc.identifier.urn	urn:nbn:de:gbv:7-11858/00-1735-0000-0028-86DE-A-9
dc.affiliation.institute	Fakultät für Physik	de
dc.identifier.ppn	848603656

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