2015/03/31 by Jonas Wiedenmann, Erwann Bocquillon, Russell S. Deacon +20 · 398 citations
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Bound state #Condensed matter physics #Electronic and Structural Properties of Oxides #Gapless playback #Insulator (electricity) #Josephson effect #Optoelectronics #Physics #Pi Josephson junction #Quantum mechanics #Superconductivity #Supercurrent #Topological Materials and Phenomena #Topological insulator #Topology (electrical circuits) #cond-mat.mes-hall #cond-mat.supr-con
paper · pdf · doi:10.1038/ncomms10303
published in Nature Communications 7(1), 10303 (Nature Portfolio) · revised version, main text : 15 pages, 4 figures, supplementary information : 34 pages, 17 figures
arxiv created 2015/10/20 · openalex publication_date 2016/01/21 · arxiv updated 2016/01/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The Josephson effect describes the generic appearance of a supercurrent in a weak link between two superconductors. Its exact physical nature deeply influences the properties of the supercurrent. In recent years, considerable efforts have focused on the coupling of superconductors to the surface states of a three-dimensional topological insulator. In such a material, an unconventional induced p-wave superconductivity should occur, with a doublet of topologically protected gapless Andreev bound states, whose energies vary 4π-periodically with the superconducting phase difference across the junction. In this article, we report the observation of an anomalous response to rf irradiation in a Josephson junction made of a HgTe weak link. The response is understood as due to a 4π-periodic contribution to the supercurrent, and its amplitude is compatible with the expected contribution of a gapless Andreev doublet. Our work opens the way to more elaborate experiments to investigate the induced superconductivity in a three-dimensional insulator.