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oai:drum.lib.umd.edu:1903/165082016-03-29T04:01:08Zcom_1903_11812com_1903_12com_1903_2269com_1903_2col_1903_2752col_1903_2800col_1903_3

Paglione, Johnpierre Ziemak, Steven Joseph Digital Repository at the University of Maryland University of Maryland (College Park, Md.) Chemical Physics 2015-06-25T05:49:34Z 2015-06-25T05:49:34Z 2015 https://doi.org/10.13016/M2CP80 http://hdl.handle.net/1903/16508 I 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 Investigation of Iron-Based and Topological Superconductors via Point-Contact Spectroscopy Dissertation Condensed matter physics Physics Materials Science 122 iron arsenide Half-Heusler Iron pnictide PCS Point-contact spectroscopy Superconductivity open.access