Regensburg 2025 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 16: Superconductivity: Properties and Electronic Structure II
TT 16.10: Talk
Tuesday, March 18, 2025, 12:00–12:15, H32
Direct evidence of pairing up to the pseudogap energy in cuprate high-temperature superconductors — Jiasen Niu1,2, Maialen Ortego Larrazabal3, Thomas Gozlinski1,2, •Yudai Sato1,2, Koen M. Bastiaans4, Tjerk Benschop1, Jian-Feng Ge1,5, Yaroslav M. Blanter4, Genda Gu6, Ingmar Swart3, and Milan P. Allan1,2 — 1Leiden Institute of Physics, Leiden University — 2Fakultät für Physik, Ludwig-Maximilians-Universität — 3Debye Institute of Nanomaterials Science — 4Kavli Institute of Nanoscience, Delft University of Technology — 5Max Planck Institute for Chemical Physics of Solids — 6Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory
In cuprate high-temperature superconductors, a pseudogap state is observed in a specific region of the phase diagram. Since it exists between the Mott insulating and superconducting phases, the origin of the peudogap is thought to be associated with electron pairing and/or a locally ordered state. Despite extensive studies, however, a definitive explanation remains elusive. Shot-noise experiments, which can directly detect electron pairing, hold the potential to resolve this long-standing debate. In this presentation, I will report on local shot-noise measurements on the unconventional superconductor Bi2Sr2Ca2CuO8+δ using scanning tunneling microscopy. We found that the pseudogap energy is associated with electron pairing, with pairing energies reaching up to 70 meV. Our results exclude the possibility of the pseudogap arising solely from local orders, and instead indicate a clear relation between the pseudogap state and Cooper pair formation.
Keywords: cuprate superconductors; pseudogap; scanning tunneling microscopy and spectroscopy; shot noise