17–21 Aug 2017
AlbaNova
Europe/Stockholm timezone

Carsten Timm - Inflated nodes and surface states in multiband super- conductors with broken time-reversal symmetry

17 Aug 2017, 16:45
35m
FB52 (AlbaNova)

FB52

AlbaNova

Description

It is commonly believed that superconductors fall into one of three classes: They can have a full energy gap, a gap with point nodes, or a gap with line nodes. We have shown in [1] that multiband, even-parity, nodal superconducting states that break time-reversal symmetry do not belong to these classes. Instead, they generically possess two-dimensional Fermi surfaces. These Fermi surfaces are generated by ? inflating? point and line nodes into spheroidal and toroidal pockets, respectively, by a pseudomagnetic field resulting from interband pairing. Such states can be energetically stable in spite of the extended Fermi surfaces. The inflated nodes are topologically protected by a Z2 invariant, which we give in terms of a Pfaffian [1]. In addition, inflated point nodes retain a nontrivial Chern number, while inflated line nodes are characterized by a second Pfaffian. Finally, I will discuss the surface states and their interplay with the inflated nodes in multiband superconductors. [1] D. F. Agterberg, P. M. R. Brydon, and C. Timm, Phys. Rev. Lett. 118, 127001 (2017).

Presentation materials

There are no materials yet.