Effects of a single magnetic impurity on superconductivity
| dc.contributor.advisor | Tanaka, Kaori | en_US |
| dc.contributor.committeeMember | Soteros, Chris | en_US |
| dc.contributor.committeeMember | Hussey, Glenn C. | en_US |
| dc.contributor.committeeMember | Gap Soo, Chang | en_US |
| dc.contributor.committeeMember | Dick, Rainer | en_US |
| dc.contributor.committeeMember | Xiao, Chijin | en_US |
| dc.creator | Pan, Sushan | en_US |
| dc.date.accessioned | 2009-01-06T12:31:50Z | en_US |
| dc.date.accessioned | 2013-01-04T04:23:19Z | |
| dc.date.available | 2010-01-12T08:00:00Z | en_US |
| dc.date.available | 2013-01-04T04:23:19Z | |
| dc.date.created | 2008 | en_US |
| dc.date.issued | 2008 | en_US |
| dc.date.submitted | 2008 | en_US |
| dc.description.abstract | Electronic structure of a conventional superconductor in the vicinity of a single, iso- lated magnetic impurity has been probed experimentally with scanning tunneling spectroscopy by Yazdani et al.. Motivated by their experiment, we study the ef- fects of a single magnetic impurity on superconductivity by means of the mean-¯eld Bogoliubov-de Gennes theory. The Bogoliubov-de Gennes equations are solved di- rectly and numerically, utilizing parallel computation on a CFI-founded 128-CPU Beowulf-class PC cluster here at the University of Saskatchewan. As a preliminary study, we also examine the electronic structure around a magnetic vortex. The local magnetic field around a vortex breaks up Cooper pairs and suppresses superconduc- tivity locally. Quasiparticle excitations are created and bound in the vortex core area due to repeated Andreev scattering. A magnetic impurity tends to align the spins of the neighboring electrons and break up Cooper pairs, and has similar effects of lo- cally suppressing superconductivity. A striking difference, however, from the vortex problem is that around a magnetic impurity there is particle-hole asymmetry in the tunneling conductance. This is due to different probability amplitudes in the spin-up branch and the spin-down branch of quasiparticle excitations. Furthermore, for the spin potential strength larger than a certain critical value, the nature of quasiparticle excitations is changed dramatically. Within a model of classical spin, we propose an explanation of the measured tunneling conductance of the experiment. This work is significant in that it gives us insight into superconductivity and magnetism{two complementary manifestation of strong electron correlations. | en_US |
| dc.identifier.uri | http://hdl.handle.net/10388/etd-01062009-123150 | en_US |
| dc.language.iso | en_US | en_US |
| dc.subject | NbSe_2 | en_US |
| dc.subject | Nb | en_US |
| dc.subject | spin potential | en_US |
| dc.subject | vortex | en_US |
| dc.title | Effects of a single magnetic impurity on superconductivity | en_US |
| dc.type.genre | Thesis | en_US |
| dc.type.material | text | en_US |
| thesis.degree.department | Physics and Engineering Physics | en_US |
| thesis.degree.discipline | Physics and Engineering Physics | en_US |
| thesis.degree.grantor | University of Saskatchewan | en_US |
| thesis.degree.level | Masters | en_US |
| thesis.degree.name | Master of Science (M.Sc.) | en_US |