Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
Phys Rev Lett. 2023 Jan 27;130(4):046402. doi: 10.1103/PhysRevLett.130.046402.
The interplay of nontrivial topology and superconductivity in condensed matter physics gives rise to exotic phenomena. However, materials are extremely rare where it is possible to explore the full details of the superconducting pairing. Here, we investigate the momentum dependence of the superconducting gap distribution in a novel Dirac material PdTe. Using high resolution, low temperature photoemission spectroscopy, we establish it as a spin-orbit coupled Dirac semimetal with the topological Fermi arc crossing the Fermi level on the (010) surface. This spin-textured surface state exhibits a fully gapped superconducting Cooper pairing structure below T_{c}∼4.5 K. Moreover, we find a node in the bulk near the Brillouin zone boundary, away from the topological Fermi arc. These observations not only demonstrate the band resolved electronic correlation between topological Fermi arc states and the way it induces Cooper pairing in PdTe, but also provide a rare case where surface and bulk states host a coexistence of nodeless and nodal gap structures enforced by spin-orbit coupling.
凝聚态物理中非平凡拓扑和超导性的相互作用产生了奇异现象。然而，在可能探索超导配对的全部细节的材料中，它们极为罕见。在这里，我们研究了新型狄拉克材料 PdTe 中超导能隙分布的动量依赖性。我们使用高分辨率、低温光电子能谱，将其确立为具有拓扑费米弧穿过（010）表面费米能级的自旋轨道耦合狄拉克半金属。这种具有自旋织构的表面态在 T_{c}∼4.5 K 以下表现出完全能隙的超导库珀配对结构。此外，我们在离拓扑费米弧较远的布里渊区边界附近的体相中发现了一个节点。这些观察结果不仅证明了拓扑费米弧态之间的能带分辨电子相关性，以及它在 PdTe 中诱导库珀配对的方式，而且还提供了一个罕见的情况，其中表面和体相态由自旋轨道耦合强制的无节点和节点隙结构共存。
