Superconducting diode effect in top-gated Josephson junctions

We theoretically investigate the non-reciprocity of the critical current in proximitized Josephson junctions (JJs) in the presence of an in-plane magnetic field. We show that the interrelation between magnetic field and Rashba spin-orbit coupling yields a superconducting diode effect (SDE) that can be modulated by tuning the junction transparency with a top gate. The critical current amplitudes are found to peak at different values of the magnetic field, in dependence of both the Rashba SOC strength and the junction transparency. We develop a simplified analytical model for narrow junctions and obtain analytical expressions for the critical currents and SDE quality factor in the low-field, high-transparency limit. The results are in qualitative agreement with recent experimental results [2] and more elaborated numerical simulations [1,2]. Our results indicate that both the in-plane magnetic field and the top gate can be used as control knobs for modulating the SDE quality factor.

[1] B. Pekerten, A. C. Prasannan, B. Scharf, and A. Matos-Abiague (unpublished).

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