Lokale Studie von ungeordneten Supraleitern
Zusammenfassung der Projektergebnisse
The superconductor-to-insulator transition in disordered superconductors has intrigued physicists for more than 30 years. The physical mechanism of the transition is explained in terms of non-magnetic disorder. We showed that surface magnetic disorder is intrinsically present in amorphous indium oxide films. Our results are obtained by high-resolution scanning tunneling microscopy using superconducting tips. They reveal previously unnoticed subgap states that are direct evidence of magnetic disorder. Our findings add a new aspect and have important consequences on the fundamental understanding of the superconductor-to-insulator transition, which gained renewed interest due to the potential applications in single-photon detectors and quantum computation. We presented a novel low temperature, STM based, shot-noise measurement apparatus with sub-atomic spatial resolution. Using our technique, we can reliably characterize single-atom junctions with a wide range of tunnel junction resistance values, while retaining the full scanning and spectroscopy capabilities of a low temperature STM. The flexibility in junction resistance values will allow future measurements also in highly non-linear junctions, e.g. of superconducting junctions.
Projektbezogene Publikationen (Auswahl)
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Direct observation of intrinsic surface magnetic disorder in amorphous superconducting films. Physical Review B, 105(14).
Tamir, Idan; Trahms, Martina; Gorniaczyk, Franzisca; von Oppen, Felix; Shahar, Dan & Franke, Katharina J.
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Shot-noise measurements of single-atom junctions using a scanning tunneling microscope. Review of Scientific Instruments, 93(2).
Tamir, Idan; Caspari, Verena; Rolf, Daniela; Lotze, Christian & Franke, Katharina J.
