Topological Superconductivity and Diode Effects in Semiconductor-Based Josephson Junctions*

We theoretically investigate the magnetic field dependence of the current-phase relation (CPR) and critical currents in planar Josephson junctions formed in a semiconducting two-dimensional electron gas proximitized by s-wave superconductors. We show how magnetic-field-induced jumps in the ground-state phase difference across the junction can be extracted from the magneto-CPR and provide a simple analytical expression for estimating the Rashba spin-orbit coupling strength from the size of the ground-state phase jumps [1]. Performing numerical simulations we reveal how to use the magneto-CPR to closely map the junction’s phase diagram and the topological gap protecting the Majorana bound states from local perturbations [1]. The ground-state phase behavior together with the phase diagram provides a robust description of the junction transition into the topological superconducting state. We also study the signatures of the superconducting diode effect (SDE) on the magneto-CPR and critical currents. We discuss possible mechanisms leading to the SDE sign changes observed in recent experiments [2,3] as well as the effects of the Rashba spin-orbit strength and junction transparency on the magnetic field dependence of the forward and reverse critical currents [1,2].

 

[1] B. Pekerten, A. C. Prasannan, B. Scharf, and A. Matos-Abiague (unpublished).

[2] N. Lotfizadeh, B. Pekerten, P. Yu, B. H. Elfeky, W. Strickland, A. Matos-Abiague, and J. Shabani, arXiv:2303.01902 (2023).

[3] A. Costa, C. Baumgartner, S. Reinhardt, J. Berger, S. Gronin, G. C. Gardner, T. Lindemann, M. J. Manfra, J. Fabian, D. Kochan, N. Paradiso, and C. Strunk, Nat. Nanotechnol. (2023).