Condensed Matter Seminar Series

Superconductivity in the Presence of Spin-Orbit Coupling--
Old Dog, New Tricks

Karen Michaeli

M.I.T.

Thursday January 31,  11:30 am,  Room 298 (tentative),  Physics Building

Abstract: The coupling between the spin of an electron and its momentum is recognized to generate a variety of new phases in condensed matter systems. For example, it has been recently demonstrated that spin-orbit coupling can change the nature of a trivial insulator to endow it with topological properties. Or, in symmetry broken states, spin-orbit coupling permits exotic low energy excitations such as skyrmions in helimagnets and Majorana modes in superconductors. The interplay between superconductivity and spin-orbit effects gives rise to additional surprising features, which I will discuss in my talk. For instance, the locking of the spin and orbital degrees of freedom can protect superconductors with unconventional pairing symmetry against disorder. Further, I will show that it stabilizes a condensate of Cooper pairs with finite momentum (a variant of the Fulde-Ferrel-Larkin-Ovchinikov state) up to high magnetic fields. More generally, in the presence of spin-orbit coupling a superconductor has a peculiar mixed state in which vortices resemble magnetic monopoles.