Non-Majorana origin of anomalous current-phase relation and Josephson diode effect in Bi<sub>2</sub>Se<sub>3</sub>/NbSe<sub>2</sub> Josephson junctions.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40512860.
- Also identified by DOI 10.1126/sciadv.adw6925 and PMC identifier 12164977.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Josephson junctions (JJs) are key to superconducting quantum technologies and the search for self-conjugate quasiparticles potentially useful for fault-tolerant quantum computing. In topological insulator (TI)-based JJs, measuring the current-phase relation (CPR) can reveal unconventional effects such as Majorana bound states (MBS) and nonreciprocal transport. However, reconstructing CPR as a function of magnetic field has not been attempted. Here, we present a platform for field-dependent CPR measurements in planar JJs made of NbSe<sub>2</sub> and few-layer Bi<sub>2</sub>Se<sub>3</sub>. When a flux quantum [Formula: see text] threads the junction, we observe anomalous peak-dip CPR structure and nonreciprocal supercurrent flow. We show that these arise from a nonuniform supercurrent distribution that also leads to a robust and tunable Josephson diode effect. Furthermore, despite numerous previous studies, we find no evidence of MBS. Our results establish magnetic field-dependent CPR as a powerful probe of TI-based superconducting devices and offer design strategies for nonreciprocal superconducting electronics.