Tunable critical supercurrent and spin-asymmetric Josephson effect in superlattices

TL;DR

This paper proposes a method to observe the spin-asymmetric Josephson effect in superlattices, demonstrating its feasibility through numerical simulations and linking it to tunable critical supercurrents in ferromagnetic Josephson junctions.

Contribution

It introduces a new approach to observe the spin-asymmetric Josephson effect using spin-dependent superlattices in ultracold gases, supported by numerical analysis.

Findings

Feasibility of observing the spin-asymmetric Josephson effect in ultracold atomic gases.

Numerical demonstration of the quantum dynamics in one dimension.

Explanation of supercurrent tunability via the spin-asymmetric Josephson effect.

Abstract

Combining the Josephson effect with magnetism, or spin dependence in general, creates novel physical phenomena. The spin-asymmetric Josephson effect is a predicted phenomenon where a spin-dependent potential applied across a Josephson junction induces a spin-polarized Josephson current. Here, we propose an approach to observe the spin-asymmetric Josephson effect with spin-dependent superlattices, realizable, e.g., in ultracold atomic gases. We show that observing this effect is feasible by studying numerically the quantum dynamics of the system in one dimension. Furthermore, we show that the enhancement, or tunability, of the critical supercurrent in ferromagnetic Josephson junctions [F. S. Bergeret, A. F. Volkov, and K. B. Efetov, Phys. Rev. Lett. 86, 3140 (2001)] can be explained by the spin-asymmetric Josephson effect.