Fig. 1: Structural and composition characterizations of a-YAlO₃/KTaO₃(111).

a HAADF-STEM image of a-YAlO₃/KTaO₃ viewed along the \([11\bar{2}]\) zone axis. The inset shows the enlarged HR-STEM image of KTaO₃ overlapped with atomic configuration. b HR-STEM image and the corresponding EDX elemental mapping of interface. c Distribution of Ta⁵⁺ ions along the [111] crystal axis of KTaO₃(111) surface. Ta⁵⁺ ions are shown with progressively smaller sizes in the three adjacent (111) planes, which are labeled as Ta-I, Ta-II, and Ta-III, respectively. d Hall bar configuration on a-YAlO₃/KTaO₃(111) heterostructure. Here, φ is defined as the in-plane azimuthal angle between the applied magnetic field B and the \([1\bar{1}0]\)-axis of the lattice, shown in the inset of d.