Suppression of thermal smearing in a feedback-driven atomic size Josephson junction
| Autor: | Escribano, Samuel D., Barrena, Víctor, Perconte, David, Moreno, Jose Antonio, Lomana, Marta Fernández, Águeda, Miguel, Herrera, Edwin, Wu, Beilun, Rodrigo, Jose Gabriel, Prada, Elsa, Guillamón, Isabel, Yeyati, Alfredo Levy, Suderow, Hermann |
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| Rok vydání: | 2023 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | The ultimate spatial limit to establish a Josephson coupling between two superconducting electrodes is an atomic-scale junction. The Josephson effect in such ultrasmall junctions has been used to unveil new switching dynamics, study coupling close to superconducting bound states or unveil non-reciprocal effects. However, coupling is weak and thermal smearing reduces the Cooper pair current magnitude. Here we show that a feedback element induces a time-dependent bistable regime which consists of periodic oscillations between two different Cooper pair tunneling states (corresponding to the DC and AC Josephson regimes respectively). The amplitude of the time-averaged current within the bistable regime is robust against thermal smearing. By tracing the periodic oscillations in the new bistable regime as a function of the position in a Scanning Tunneling Microscope (STM), we obtain atomic scale map of the critical current in 2H-NbSe$_2$ and find spatial modulations due to a pair density wave. Our results fundamentally improve our understanding of atomic size Josephson junctions and provide a promising new route to study superconducting materials through atomic scale maps of the Josephson coupling. Comment: 51 pages, 14 figures |
| Databáze: | arXiv |
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