Repository logo

Effects of a single magnetic impurity on superconductivity

dc.contributor.advisorTanaka, Kaorien_US
dc.contributor.committeeMemberSoteros, Chrisen_US
dc.contributor.committeeMemberHussey, Glenn C.en_US
dc.contributor.committeeMemberGap Soo, Changen_US
dc.contributor.committeeMemberDick, Raineren_US
dc.contributor.committeeMemberXiao, Chijinen_US
dc.creatorPan, Sushanen_US
dc.description.abstractElectronic 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.subjectspin potentialen_US
dc.titleEffects of a single magnetic impurity on superconductivityen_US
dc.type.materialtexten_US and Engineering Physicsen_US and Engineering Physicsen_US of Saskatchewanen_US of Science (M.Sc.)en_US


Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
1.86 MB
Adobe Portable Document Format
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
905 B
Plain Text