Scanning Tunneling Spectroscopy of Subsurface Non-Magnetic Impurities in Copper

Kotzott, Thomas Ulrich

dc.contributor.advisor	Wenderoth, Martin PD Dr.
dc.contributor.author	Kotzott, Thomas Ulrich
dc.date.accessioned	2021-09-06T11:37:02Z
dc.date.available	2022-07-20T00:50:15Z
dc.date.issued	2021-09-06
dc.identifier.uri	http://hdl.handle.net/21.11130/00-1735-0000-0008-58FD-9
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-8807
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-8807
dc.language.iso	eng	de
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject.ddc	530	de
dc.title	Scanning Tunneling Spectroscopy of Subsurface Non-Magnetic Impurities in Copper	de
dc.type	doctoralThesis	de
dc.contributor.referee	Wenderoth, Martin PD Dr.
dc.date.examination	2021-07-22
dc.subject.gok	Physik (PPN621336750)	de
dc.description.abstracteng	In this thesis, single non-magnetic Ge and Ag impurities buried in the bulk metal Cu are studied to characterize their scattering properties as well as the electronic structure of the host. This is possible by analyzing the surface interference patterns in the local density of states that form by directionally propagating electrons due to electron focusing and are mapped by low temperature scanning tunneling microscopy and scanning tunneling spectroscopy. Signatures of impurities buried up to the 18th monolayer can be identified on the Cu(100) surface. In order to distinguish contributions from impurity scattering and the host, we compare the isoelectronic d scatterer Ag and the sp scatterer Ge in dilute Cu alloys. Both species show resembling topographic patterns, which is reflected in similar effective scattering phase shifts that are extracted using a plane wave tight-binding model. Comparing ab-initio calculations with the experimental data suggests incoherent scattering processes of electrons with sp character at the Ge impurity. Because the studied atomic species are spectroscopically inconspicuous, the energy-resolved interference patterns of a buried impurity act as real-space signatures of the electronic structure of Cu. In addition to the Cu dispersion, we find in the experimental data for both species a kink at zero bias that we attribute to a band structure renormalization due to many-body interactions. It can be described by a Debye self-energy with an electron-phonon coupling parameter of λ=5. As possible explanation, electron-phonon coupling of bulk electrons in the vicinity of the surface is discussed. We find that the surface scattering patterns allow us to characterize bulk scattering impurities as well as to map the bulk band renormalization and thus provide a real-space signature of many-body effects within a solid.	de
dc.contributor.coReferee	Jooß, Christian Prof. Dr.
dc.subject.eng	scanning tunneling microscopy	de
dc.subject.eng	scanning tunneling spectroscopy	de
dc.subject.eng	subsurface impurities	de
dc.subject.eng	dilute alloys	de
dc.subject.eng	Friedel oscillations	de
dc.subject.eng	orbital-resolved electron focusing	de
dc.subject.eng	scattering phase shift	de
dc.subject.eng	electron-phonon coupling	de
dc.subject.eng	many-body effects	de
dc.subject.eng	electronic structure renormalization	de
dc.subject.eng	self-energy	de
dc.identifier.urn	urn:nbn:de:gbv:7-21.11130/00-1735-0000-0008-58FD-9-2
dc.affiliation.institute	Fakultät für Physik	de
dc.description.embargoed	2022-07-20
dc.identifier.ppn	1769509224

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