Induced unconventional superconductivity on the surface states of Bi2Te3topological insulator

• Published in: Nature Communications
• Main Authors: Charpentier, Sophie, Galletti, Luca, Kunakova, Gunta, Arpaia, Riccardo, Song, Yuxin, Baghdadi, Reza, Wang, Shu Min, Kalaboukhov, Alexei, Olsson, Eva, Tafuri, Francesco, Golubev, Dmitry, Linder, Jacob, Bauch, Thilo, Lombardi, Floriana
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Chemistry (all); Biochemistry; Genetics and Molecular Biology (all); Physics and Astronomy (all); IPY
• Online Access: http://hdl.handle.net/11588/697056; https://doi.org/10.1038/s41467-017-02069-z; http://www.nature.com/ncomms/index.html

Topological superconductivity is central to a variety of novel phenomena involving the interplay between topologically ordered phases and broken-symmetry states. The key ingredient is an unconventional order parameter, with an orbital component containing a chiral px + ipy wave term. Here we present phase-sensitive measurements, based on the quantum interference in nanoscale Josephson junctions, realized by using Bi2Te3 topological insulator. We demonstrate that the induced superconductivity is unconventional and consistent with a sign-changing order parameter, such as a chiral px + ipy component. The magnetic field pattern of the junctions shows a dip at zero externally applied magnetic field, which is an incontrovertible signature of the simultaneous existence of 0 and π coupling within the junction, inherent to a non trivial order parameter phase. The nano-textured morphology of the Bi2Te3 flakes, and the dramatic role played by thermal strain are the surprising key factors for the display of an unconventional induced order parameter.