Berlin 2015 – wissenschaftliches Programm
TT 21.2: Poster
Montag, 16. März 2015, 15:00–18:00, Poster B
Leggett modes in superconductors without inversion symmetry — •Nikolaj Bittner1, Dietrich Einzel2, Ludwig Klam1, and Dirk Manske1 — 1Max–Planck–Institut für Festkörperforschung, D–70569 Stuttgart, Germany — 2Walther–Meißner–Institut für Tieftemperaturforschung, D–85748 Garching, Germany
The recent discovery of bulk superconductors without inversion symmetry has allowed for a new understanding of pairing correlations in general. These so–called non–centorsymmetric superconductors (NCS) are characterized by the existence of an antisymmetric spin–orbit coupling. As a consequence, there occurs a band splitting, accompanied with the coexistence of both singlet and triplet contributions to the superconducting gap. The band splitting implies the existence of a new massive collective mode, which was discovered by A. J. Leggett in 1966 for ordinary two–band superconductors, the so–called Leggett mode. Within the framework of the (Nambu) Matrix Kinetic Theory we show, that (i) in contrast to the case of the ordinary two–band superconductors, where the Leggett mode appears always as a massive collective excitation, its counterpart in NCS systems can be massless under certain conditions, (ii) it survives in the limit of vanishing triplet admixture t = Δ tr/Δs to the singlet energy gap and (iii) Anderson–Higgs mechanism leaves its mass unaffected.