Fabry-Perot superconducting diode

Superconducting diode effects (SDEs) occur in systems with asymmetric critical supercurrents |Iᶜ₊|≠ |Iᶜ₋| yielding dissipationless flow in one direction $(e.g., +)$, while dissipative transport in the opposite direction $(-)$. Here we investigate the SDE in a phase-biased φ Josephson junction with a double-barrier resonant-tunneling InAs nanowire nested between proximitized InAs/Al leads with finite momentum q Cooper pairing. Within the Bogoliubov-de Gennes (BdG) approach, we obtain the exact BCS ground state energy EG(q,φ) and Iᶜ₊ ≠ |Iᶜ₋| from the current-phase relation IG(q,φ) ~ ∂φEG(q,φ). The SDE arises from the accrued Andreev phase shifts δ φL,R(q,φ) leading to asymmetric BdG spectra for q≠ 0. Remarkably, the diode efficiency γ=(Iᶜ₊ - |Iᶜ₋|)/(Iᶜ₊ + |Iᶜ₋|) shows multiple Fabry-Perot resonances γ 26% at the double-barrier Andreev bound states as the well depth Vg is varied. Our γ also features sign reversals for increasing q and high sensitiveness to fermion-parity transitions. The latter enables Iᶜ₊ (φ₊) Iᶜ₋(φ₋) switchings over narrow phase windows, i.e., φ₊, φ₋ ∈ Δ φπ, possibly relevant for future superconducting electronics.