Rashba-type oxide interfaces provide an important platform for exploring spintronic effects, unconventional superconductivity, and nonlinear transport in non-centrosymmetric systems. Here, we report nonlinear electrical transport in two-dimensional electron gases (2DEGs) at KTaO₃-based interfaces, spanning both the normal state and the superconducting fluctuation regime. In the normal state, we observe a large nonlinear transverse response governed by the Berry curvature triple[1]. Entering the superconducting fluctuation regime, a pronounced nonreciprocal magnetotransport emerges, accompanied by a sign reversal with temperature. Combined with theoretical analysis, these results indicate mixed-parity pairing with a finite spin-triplet component[2]. Furthermore, we demonstrate a giant unidirectional magnetoresistance (UMR) in a magnetic interface superconductor, providing a sensitive probe of triplet pairing and charge–spin conversion[3]. These findings establish oxide Rashba interfaces as a promising platform for investigating unconventional superconductivity and enabling nonlinear electronic functionalities.

[1] J. Zhai^#, M. Trama^#, H. Liu, Z. Zhu, Y. Zhu, C. A. Perroni, R. Citro^*, P. He^*, J. Shen^*. Large Nonlinear Transverse Conductivity and Berry Curvature in KTaO₃ Based Two-Dimensional Electron Gas. Nano Letters,23, 11892-11898 (2023).

[2] Jinfeng Zhai^#, Taekoo Oh^#, Hao Liu, Chaoyu Pan, Naoto Nagaosa*, Pan He* and Jian Shen*. Nonreciprocal transport in KTaO3-based interface superconductors with parity-mixing, Phys. Rev. Lett, 134, 236303 (2025).

[3] Unpublished.