Induced unconventional superconductivity on the surface states of Bi2Te3 topological insulator

• DOI: 10.1038/s41467-017-02069-z
• Publication Date: 2017-12-04T17:57:48Z
• Authors: Sophie Charpentier; Luca Galletti; Gunta Kunakova; Riccardo Arpaia; Yuxin Song; Reza Baghdadi; Shu Min Wang; Alexei Kalaboukhov; Eva Olsson; Francesco Tafuri; Dmitry Golubev; Jacob Linder; Thilo Bauch; Floriana Lombardi
• Keywords: Genetics and Molecular Biology (all); Science; Condensed Matter - Superconductivity; Chemistry (all); Q; FOS: Physical sciences; -; 02 engineering and technology; Biochemistry; 01 natural sciences; Article; Superconductivity (cond-mat.supr-con); Physics and Astronomy (all); 0103 physical sciences; Chemistry (all); Biochemistry, Genetics and Molecular Biology (all); Physics and Astronomy (all); 0210 nano-technology

AbstractTopological 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 p x + ip y 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 p x + ip y 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.