Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 57: Superconductivity: Properties and Electronic Structure
TT 57.4: Talk
Thursday, April 4, 2019, 15:45–16:00, H7
Superconducting Higgs mode in cuprates — •Min-Jae Kim1,4, Hao Chu1,4, Kota Katsumi2, Sergey Kovalev3, Robert David Dawson1, Lukas Schwarz1, Naotaka Yoshikawa2, Gideok Kim1, Daniel Putzky1, Georg Cristiani1, Gennady Logvenov1, Andreas Schnyder1, Dirk Manske1, Michael Gensch3, Zhe Wang3, Ryo Shimano2, and Stefan Kaiser1,4 — 1Max Planck Institute for Solid State Research, Stuttgart, Germany — 2University of Tokyo, Japan — 3Helmholtz-Zentrum Dresden- Rossendorf, Germany — 44th Physics Institute, University of Stuttgart, Germany
The complex phase diagram of cuprate high-Tc superconductor is due to an intriguing interplay of different orders such as the pseudogap, or charge order. Despite intensive spectroscopic measurements of these ordered states, yet the microscopic mechanism behind high-Tc superconductivity is still lacking. In particular the collective dynamics of the superconducting order parameter, the Higgs mode, was not accessible so far. Here we report on *Higgs spectroscopy* in cuprate superconductors that we accomplished by using a high-field multicycle THz pulse, which nonlinearly couples to the superconducting condensate and leads to characteristic third harmonic generation. We identify the driven Higgs amplitude response of the superconducting order parameter in three archetypal families of cuprate thin films and we report on a novel collective mode universally exhibited by optimally doped samples. In addition, we find a finite Higgs-like response above Tc that might be interpreted as finite pairing amplitude even above Tc.