Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 14: Superconductivity: (General) Theory
TT 14.8: Vortrag
Montag, 7. März 2016, 17:15–17:30, H19
The Higgs-mode in charged superconductors without particle-hole symmetry — •Matthias Hecker — KIT, Karlsruhe
In a charged BCS superconductor there are two collective modes, namely the amplitude or Higgs mode and the plasmon mode reflecting the fact that due to long range Coulomb interactions phase fluctuations are shifted to the plasmon energy. Usually, the experimental determination of the Higgs mode is challenging as its energy sits right at the edge of the quasi-particle continuum. Using a field integral approach we investigate the possibility of detecting the Higgs mode by measuring density-density correlations. Without the assumption of particle-hole symmetry there is a finite coupling between the two excitation modes which is usually suppressed by the small factor Δ0/EF. However, in doped SrTiO3 the latter ratio is of the order Δ0/EF≈ 10−1. We explore whether this coupling is sufficient to exploit the experimentally easy access to charge excitations in order to detect a Higgs mode signal.