Regensburg 2010 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 9: SC: Poster Session
TT 9.32: Poster
Monday, March 22, 2010, 14:00–18:00, Poster A
Gauge modes in non-centrosymmetric superconductors — •Ludwig Klam1, Dietrich Einzel2, and Dirk Manske1 — 1Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart — 2Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, D-8548 Garching
It is well-known, that the broken gauge symmetry characterizing the ground state of conventional BCS-superconductors is reflected in the existence of a gapless collective mode, the so-called Anderson-Bogoliubov or gauge mode. Besides other possible collective mode excitations, it is the gauge mode, that exists also in unconventional superconductors, which can be described by order parameters with more than two components. In this contribution, we investigate the structure and the role of the gauge mode in a class of superconductors without inversion center. In these so-called non-centrosymmetric superconductors (NCS), a parity violating antisymmetric spin-orbit coupling (ASOC) gives rise to a band splitting and causes the possible coexistence of singlet and triplet contributions to the superconducting order parameter. Using the Nambu kinetic equation approach, we present a comprehensive analysis of the gauge mode in NCS. Particular emphasis will be on (i) its ultimate necessity for the existence of the charge conservation law and (ii) the prediction of a splitting of the gauge mode into two branches, located on the two bands, with increasing strength of the ASOC.