Topological superconductors are an essential component for topologically protected quantum computation and information processing. Although signatures of topological superconductivity have been reported in heterostructures, material realizations of intrinsic topological superconductors are rather rare. Here we use scanning tunnelling spectroscopy to study the transition metal dichalcogenide 4Hb-TaS₂ that interleaves superconducting 1H-TaS₂ layers with strongly correlated 1T-TaS₂ layers, and find spectroscopic evidence for the existence of topological surface superconductivity. These include edge modes running along the 1H-layer terminations as well as under the 1T-layer terminations, where they separate between superconducting regions of distinct topological nature. We also observe signatures of zero-bias states in vortex cores. All the boundary modes exhibit crystallographic anisotropy, which—together with a finite in-gap density of states throughout the 1H layers—allude to the presence of a topological nodal-point superconducting state. Our theoretical modelling attributes this phenomenology to an inter-orbital pairing channel that necessitates the combination of surface mirror symmetry breaking and strong interactions. It, thus, suggests a topological superconducting state realized in a natural compound.

拓扑超导体是拓扑保护量子计算和信息处理的重要组成部分。尽管已经在异质结构中报道了拓扑超导的特征，但本征拓扑超导体的材料实现相当罕见。在这里，我们使用扫描隧道光谱来研究将超导 1H-TaS ₂层与强相关 1T-TaS ₂交错的过渡金属二硫属化物 4Hb- TaS ₂层，并找到拓扑表面超导存在的光谱证据。这些包括沿 1H 层终端以及在 1T 层终端下运行的边缘模式，它们在不同拓扑性质的超导区域之间分离。我们还观察到涡核中零偏置状态的特征。所有边界模式都表现出晶体学各向异性，这与整个 1H 层中有限的间隙内状态密度一起暗示了拓扑节点超导状态的存在。我们的理论建模将这种现象学归因于轨道间配对通道，该通道需要结合表面镜像对称性破坏和强相互作用。因此，它暗示了在天然化合物中实现的拓扑超导状态。