Interferometric Evidence of Nonvolatile Anomalous Phase Shifts in Exchange-Spin-Split Josephson Supercurrent Diodes.

Jeon, Kun-Rok; Kim, Jae-Keun; Yoon, Jiho; Jeon, Jae-Chun; Han, Hyeon; Cottet, Audrey; Kontos, Takis; Parkin, Stuart S P · ACS Nano · 2026

basic_science · Level V

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Abstract

The recent realization of zero-field, polarity-reversible supercurrent rectification in proximity-magnetized Rashba-type Pt Josephson junctions (JJs) enables the development of superconducting logic circuits and cryogenic memory applications. Here, we demonstrate a <i>nonvolatile</i> anomalous phase shift φ<sub>0</sub> directly probed via superconducting quantum interferometry, providing phase-sensitive evidence of spontaneous time-reversal symmetry breaking in these Rashba-type systems. By replacing the Pt barrier with 5d or 4d element layers exhibiting different (para)magnetic susceptibilities, spin-orbit coupling properties, and electronic band structures, we elucidate the role of proximity effects in governing zero-field diode behavior. Ta (W) JJs exhibit zero-field diode efficiencies of ∼17% (∼5%) at 2 K, which are slightly (significantly) lower than those of Pt JJs. Notably, the diode polarity in Ta and W JJs is reversed relative to that in Pt JJs. Combined with the large zero-field diode efficiency (∼15% at 2 K) observed in highly magnetic-susceptible Pd JJs, these results show that nonvolatile φ<sub>0</sub> and, consequently, zero-field diode performance can be tuned through proximity engineering of interfacial magnetic ordering and Rashba spin-orbit interaction.