窄带隙绝缘体FeSb2中的关联拓扑极化表面态
Correlated topological-polarization surface states in the narrow-gap insulator FeSb2
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中文总结 AI 辅助
该研究以FeSb2外延薄膜为对象，利用拓扑极化原理，发现其存在受块体强关联支配的金属极性表面态，证实关联拓扑体系的块体-边界对应关系，并通过静电门控实现其量子相变，确立了拓扑极化作为关联拓扑相的设计原理。
中文摘要 AI 辅助
强电子关联与能带拓扑各自产生丰富的量子相，但二者所需的元素条件存在冲突，长期以来大多相互分离。拓扑极化提供了将二者结合的途径，可通过成键电荷产生极性表面态，无需自旋轨道耦合，从而将能带拓扑拓展到关联的3d过渡金属化合物。本文证明，窄带隙绝缘体FeSb2的外延薄膜具有拓扑极化起源的金属极性表面态，该表面态受块体强关联作用支配。非互易表面输运仅在低于块体Fe 3d轨道占据的关联驱动重构起始温度时出现，为关联拓扑体系中的块体-边界对应关系提供了直接证据。此外，静电门控可使该关联表面发生量子相变，进入铁磁态或可能的反常磁性态。本研究结果确立了拓扑极化作为广泛材料中关联拓扑相的设计原理。
英文摘要
Strong electron correlations and band topology each generate rich quantum phases, but conflicting elemental requirements have largely kept them apart. Topological polarization offers a route to unite them, producing polar surface states from bonding charge without spin-orbit coupling and thereby extending band topology to correlated 3d transition-metal compounds. Here we demonstrate that epitaxial thin films of the narrow-gap insulator FeSb2 host metallic polar surface states of topological-polarization origin, governed by the strong correlations of the bulk. Nonreciprocal surface transport emerges only below the onset temperature of a correlation-driven reconstruction of the bulk Fe 3d orbital occupation, providing direct evidence of bulk-edge correspondence in a correlated topological system. Moreover, electrostatic gating drives this correlated surface across a quantum phase transition into a ferromagnetic or possibly altermagnetic state. Our results establish topological polarization as a design principle for correlated topological phases in a broad range of materials.
