Local and nonlocal Josephson effect in ultraclean carbon nanotube-based junctions
CPfS Seminar
- Datum: 10.12.2025
- Uhrzeit: 15:00 - 16:30
- Vortragende(r): Dr. Samy Annabi
- Ecole Polytechnique, Paris
- Ort: MPI CPfS
- Raum: Seminar rooms 1-2
Andreev bound states (ABS) are fermionic states localised at the weak link of a Josephson junction. They carry a supercurrent that flows coherently through the device with an amplitude depending on the superconducting phase difference across the junction: it's the Josephson effect. When two junctions are in close proximity, their ABS hybridize, forming an Andreev molecule in which the supercurrent in one junction is influenced by the phase difference across the other, leading to a nonlocal Josephson effect.
We present here the experimental observation of this nonlocal effect in carbon nanotube-based Josephson junctions, an elementary and highly tunable platform for exploring mesoscopic superconducting transport. By developing a novel nanoassembly technique, we fabricated ultraclean CNT-based junctions, enabling the measurement of a sizeable Josephson effect with a distinctive fourfold periodicity linked to the intrinsic symmetries of the weak link. This system allows for a comprehensive study of ABS hybridization in an Andreev molecule, revealing strong interdot coupling and offering new insights into superconducting transport at the nanoscale.