4π-periodic Josephson supercurrent in HgTe-based topological Josephson junctions
| Autor: | Koji Ishibashi, C. Brüne, O. Herrmann, Russell S. Deacon, Laurens W. Molenkamp, Seigo Tarucha, Jonas Wiedenmann, E. Bocquillon, Simon Hartinger, T. M. Klapwijk, Charles Gould, C. Ames, Hartmut Buhmann, Akira Oiwa, Luis Maier |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Josephson effect
Science General Physics and Astronomy 02 engineering and technology 01 natural sciences Article General Biochemistry Genetics and Molecular Biology Pi Josephson junction Gapless playback Quantum mechanics Condensed Matter::Superconductivity 0103 physical sciences Bound state 010306 general physics ddc:537 Physics Superconductivity Condensed Matter::Quantum Gases Multidisciplinary Condensed matter physics Condensed Matter - Mesoscale and Nanoscale Physics Condensed Matter - Superconductivity Supercurrent General Chemistry 021001 nanoscience & nanotechnology Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Amplitude Topological insulator 0210 nano-technology |
| Zdroj: | Nature Communications, Vol 7, Iss 1, Pp 1-7 (2016) Nature Communications |
| ISSN: | 2041-1723 |
| Popis: | The Josephson effect describes the generic appearance of a supercurrent in a weak link between two superconductors. Its exact physical nature however deeply influences the properties of the supercurrent. Detailed studies of Josephson junctions can reveal microscopic properties of the superconducting pairing (spin-triplet correlations, $d$-wave symmetry) or of the electronic transport (quantum dot, ballistic channels). In recent years, considerable efforts have focused on the coupling of superconductors to topological insulators, in which transport is mediated by topologically protected Dirac surface states with helical spin polarization (while the bulk remains insulating). Here, the proximity of a superconductor is predicted to give rise to unconventional induced $p$-wave superconductivity, with a doublet of topologically protected gapless Andreev bound states, whose energies varies $4\pi$-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 with a weak link of the 3D topological insulator HgTe. The response is understood as due to a $4\pi$-periodic contribution to the supercurrent, and its amplitude is compatible with the expected contribution of a gapless Andreev doublet. Comment: revised version, main text : 15 pages, 4 figures, supplementary information : 34 pages, 17 figures |
| Databáze: | OpenAIRE |
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