Twist-angle-controlled Hall response in SrRuO₃ ultrathin films via van der Waals stacking

Inspired by twist-angle engineering in moiré-related two-dimensional van der Waals systems, we explore whether similar interfacial symmetry control can be extended to strongly correlated oxide systems. In this work, we demonstrate this concept by creating twist-angle-defined van der Waals interfaces through stacking of freestanding SrRuO₃ layers onto epitaxial SrRuO₃/SrTiO₃ thin films. Density functional theory (DFT) calculations show that the stacking configuration significantly influences the Dzyaloshinskii-Moriya interaction (DMI), with 45° rotation enhancing DMI by more than an order of magnitude compared to 0° alignment. Systematic magnetotransport measurements show that 45° stacking induces more pronounced changes in both the anomalous Hall effect (AHE) and the topological Hall effect (THE)-like signal, with the amplitude of the latter reaching ∼ 0.032 Ω at 45° versus only ∼ 0.008 Ω at 0° in 20 nm films. Our findings demonstrate that van der Waals stacking of correlated oxide thin films provides a non-epitaxial approach for tuning magnetotransport properties through interfacial symmetry breaking.