Field-Enhanced Critical Current and Tunable Skewness in Altermagnetic Josephson Junctions

We study the influence of external electric and Zeeman fields on the Josephson response of a planar superconductor/altermagnet/superconductor junction. We show that the critical Josephson current across the junction oscillates as the altermagnetic field strength increases. The current-phase relation can be forward- or backward-skewed due to significant second-order Josephson response. It decisively depends on the altermagnetic field strength. We discover that the skewness can be manipulated by electric gating. We reveal two additional impacts of external fields on the Josephson current: (i) Fields can induce 0-π transitions. (ii) Fields can substantially enhance the critical current.