Investigation of Iron-Based and Topological Superconductors via Point-Contact Spectroscopy

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dc.contributor.advisorPaglione, Johnpierreen_US
dc.contributor.authorZiemak, Steven Josephen_US
dc.contributor.departmentChemical Physicsen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2015-06-25T05:49:34Z
dc.date.available2015-06-25T05:49:34Z
dc.date.issued2015en_US
dc.description.abstractI report results of point-contact spectroscopy (PCS) measurements preformed on a variety of superconductors which are predicted to exhibit unconventional Cooper pairing mechanisms. Point-contact spectra of the iron pnictide BaFe_{1-x}$Pt$_x$As$_2$ are consistent with a two-gap isotropic s-wave model. This conclusion is supported by previously published results from thermal conductivity, angle-resolved photoemission spectroscopy (ARPES), and Raman spectroscopy, which confirm a lack of nodes in the order parameter and the presence of a gap of magnitude 3 meV. Conductivity spectra were also measured for the half-Heusler materials YPtBi and LuPdBi using the soft point contact method. I argue that the repeated observation of a single peak in $dI/dV$ at zero bias is not consistent with a conventional $s$-wave model. Based on attempts to fit my data to the Blonder-Tinkham-Klapwijk theory and comparison to previous experimental and theoretical work, I conclude that my results are most consistent with a model of triplet Cooper pairs and an order parameter with an odd-parity component.en_US
dc.identifierhttps://doi.org/10.13016/M2CP80
dc.identifier.urihttp://hdl.handle.net/1903/16508
dc.language.isoenen_US
dc.subject.pqcontrolledCondensed matter physicsen_US
dc.subject.pqcontrolledPhysicsen_US
dc.subject.pqcontrolledMaterials Scienceen_US
dc.subject.pquncontrolled122 iron arsenideen_US
dc.subject.pquncontrolledHalf-Heusleren_US
dc.subject.pquncontrolledIron pnictideen_US
dc.subject.pquncontrolledPCSen_US
dc.subject.pquncontrolledPoint-contact spectroscopyen_US
dc.subject.pquncontrolledSuperconductivityen_US
dc.titleInvestigation of Iron-Based and Topological Superconductors via Point-Contact Spectroscopyen_US
dc.typeDissertationen_US

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