В четверг 27 февраля в 14:00 в 226.5 ЛК состоится семинар Центра перспективных методов мезофизики нанотехнологий. С докладом на тему "Searching for Majorana Physics in Bi2Se3/NbSe2 Josephson Junctions via Current-Phase Relation measurements" Андрей Кудряшов.
Аннотация: The interplay between superconductivity and topology creates ideal conditions for engineering Majorana bound states (MBSs), non-Abelian quasiparticles with potential applications in fault-tolerant quantum computing.
Current-phase relation (CPR) measurements in Josephson junctions (JJs) with topological insulators (TIs) as weak links serve as a powerful technique to identify signatures of MBSs and differentiate them from trivial effects.
Here, using an asymmetric SQUID technique, we probe the CPR in planar van der Waals (vdW) JJ combining the superconducting NbSe$_2$ and few layer thick Bi$_2$Se$_3$ (TI). When one flux quantum threads the junction, we observe an anomalous peak-dip structure in the CPR that initially appears consistent with that expected when MBSs hybridize at the edge of the junction. Our detailed analysis, nevertheless, reveals that this anomaly stems from a non-uniform supercurrent distribution that generates a peculiar non-reciprocal CPR with complex magnetic field dependence. We furthermore demonstrate, that this non-reciprocity gives rise to a robust Josephson diode effect with nearly 30$\%$ efficiency. Our findings not only demonstrate the absence of MBS signatures near single flux quantum conditions but also illuminate new aspects of directional transport in superconducting systems, providing design principles for non-reciprocal devices.