Seminars & Lectures
| * TITLE | Topological Superconductivity Close to Van Hove Singularities in 2D | ||||||
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| * DATE / TIME | 2013-07-13, 4:30 ~ 6:30 PM | ||||||
| * PLACE | Physics Seminar room (Science Bldg, 3-201) | ||||||
| * ABSTRACT | |||||||
| We investigate unconventional superconductivity induced by weak repulsive interactions in 2D electronic systems exactly at van Hove singularities. We distinguish two types of van Hove saddle points: type-I (type-II) saddle points at time-reversal invariant (non-invariant) momenta in the Brillouin zone. For type-II van Hove systems and in the limit of weak repulsive interactions, renormalization group treatment shows that the ground state favors triplet pairing (e.g. p-wave) when the Fermi surface is not close to perfect nesting. When the 2D lattice in question respects tetragonal or hexagonal point group symmetry, topological superconductivity (e.g. chiral p+ip pairing) will generally occur. We shall also discuss implications of this study to recently discovered superconductors LaO$_{1-x}$F$_x$BiS$_2$ where type-II van Hove singularities have been realized. | |||||||
