Sessi Paolo, Fan Feng-Ren, Küster Felix, Manna Kaustuv, Schröter Niels B M, Ji Jing-Rong, Stolz Samuel, Krieger Jonas A, Pei Ding, Kim Timur K, Dudin Pavel, Cacho Cephise, Widmer Roland, Borrmann Horst, Shi Wujun, Chang Kai, Sun Yan, Felser Claudia, Parkin Stuart S P
Max Planck Institute of Microstructure Physics, Halle, 06120, Germany.
Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany.
Nat Commun. 2020 Jul 14;11(1):3507. doi: 10.1038/s41467-020-17261-x.
It has recently been proposed that combining chirality with topological band theory results in a totally new class of fermions. Understanding how these unconventional quasiparticles propagate and interact remains largely unexplored so far. Here, we use scanning tunneling microscopy to visualize the electronic properties of the prototypical chiral topological semimetal PdGa. We reveal chiral quantum interference patterns of opposite spiraling directions for the two PdGa enantiomers, a direct manifestation of the change of sign of their Chern number. Additionally, we demonstrate that PdGa remains topologically non-trivial over a large energy range, experimentally detecting Fermi arcs in an energy window of more than 1.6 eV that is symmetrically centered around the Fermi level. These results are a consequence of the deep connection between chirality in real and reciprocal space in this class of materials, and, thereby, establish PdGa as an ideal topological chiral semimetal.
最近有人提出，将手性与拓扑能带理论相结合会产生一类全新的费米子。到目前为止，对于这些非常规准粒子如何传播和相互作用的理解在很大程度上仍未得到探索。在这里，我们使用扫描隧道显微镜来可视化典型的手性拓扑半金属PdGa的电子特性。我们揭示了两种PdGa对映体具有相反螺旋方向的手性量子干涉图案，这是其陈数符号变化的直接表现。此外，我们证明PdGa在很大的能量范围内保持拓扑非平凡性，在以费米能级为对称中心的超过1.6 eV的能量窗口中通过实验检测到费米弧。这些结果是这类材料中实空间和倒易空间中的手性之间深度联系的结果，从而将PdGa确立为理想的拓扑手性半金属。
