Unexpected superconductivity at nanoscale junctions made on the topological crystalline insulator Pb0.6Sn0.4Te

• Published in: Applied physics letters Vol. 109; no. 13
• Main Authors: Das, Shekhar, Aggarwal, Leena, Roychowdhury, Subhajit, Aslam, Mohammad, Gayen, Sirshendu, Biswas, Kanishka, Sheet, Goutam
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 26.09.2016
• Subjects: Applied physics; Crystal structure; Crystallinity; Phase transitions; Superconductivity; Transition temperature
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4963698

Discovery of exotic phases of matter from the topologically non-trivial systems not only makes the research on topological materials more interesting but also enriches our understanding of the fascinating physics of such materials. Pb0.6Sn0.4Te was recently shown to be a topological crystalline insulator. Here, we show that by forming a mesoscopic point-contact using a normal non-superconducting elemental metal on the surface of Pb0.6Sn0.4Te, a superconducting phase is created locally in a confined region under the point-contact. This happens when the bulk of the sample remains to be non-superconducting, and the superconducting phase emerges as a nano-droplet under the point-contact. The superconducting phase shows a high transition temperature Tc that varies for different point-contacts and falls in a range between 3.7 K and 6.5 K. Therefore, this Letter presents the discovery of a superconducting phase on the surface of a topological crystalline insulator, and the discovery is expected to shed light on the mechanism of induced superconductivity in topologically non-trivial systems in general.