Three-dimensional strontium ruthenate (${\mathrm{SrRuO}}_3$) is an itinerant ferromagnet that features Weyl points acting as sources of emergent magnetic fields, anomalous Hall conductivity, and unconventional spin dynamics. Integrating ${\mathrm{SrRuO}}_3$ in oxide heterostructures is potentially a novel route to engineer emergent electrodynamics, but its electronic band topology in the two-dimensional limit remains unknown. Here we show that ultrathin ${\mathrm{SrRuO}}_3$ exhibits spin-polarized topologically nontrivial bands at the Fermi energy. Their band anticrossings show an enhanced Berry curvature and act as competing sources of emergent magnetic fields. We control their balance by designing heterostructures with symmetric (${\mathrm{SrTiO}}_3$/${\mathrm{SrRuO}}_3$/${\mathrm{SrTiO}}_3$ and ${\mathrm{SrIrO}}_3$/${\mathrm{SrRuO}}_3$/${\mathrm{SrIrO}}_3$) and asymmetric interfaces (${\mathrm{SrTiO}}_3$/${\mathrm{SrRuO}}_3$/${\mathrm{SrIrO}}_3$). Symmetric structures exhibit an interface-tunable single-channel anomalous Hall effect, while ultrathin ${\mathrm{SrRuO}}_3$ embedded in asymmetric structures shows humplike features consistent with multiple Hall contributions. The band topology of two-dimensional ${\mathrm{SrRuO}}_3$ proposed here naturally accounts for these observations and harmonizes a large body of experimental results.

中文翻译：

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氧化物界面处的贝里相工程

三维钌酸锶（${锶}_3$）是一种流动性铁磁体，其特征是Weyl点充当了产生磁场，异常霍尔电导率和非常规自旋动力学的来源。整合${锶}_3$氧化物异质结构中的分子结构可能是工程化新兴电动力学的一种新颖途径，但其在二维极限内的电子能带拓扑仍然未知。在这里我们展示了超薄${锶}_3$在费米能量处表现出自旋极化的拓扑非平凡带。它们的能带反交叉显示出增强的贝里曲率，并充当了新兴磁场的竞争源。我们通过设计具有对称（${\mathrm{钛酸锶}}_3$/${锶}_3$/${\mathrm{钛酸锶}}_3$ 和 ${\mathrm{斯罗}}_3$/${锶}_3$/${\mathrm{斯罗}}_3$）和非对称接口（${\mathrm{钛酸锶}}_3$/${锶}_3$/${\mathrm{斯罗}}_3$）。对称结构具有界面可调的单通道异常霍尔效应，而超薄结构${锶}_3$嵌入非对称结构中显示出与多个霍尔贡献一致的峰状特征。二维带状拓扑${锶}_3$ 这里提出的建议自然可以解释这些观察结果，并协调大量的实验结果。