论文标题
手性费米斯半学COSI中拓扑费米弧状态的准粒子干扰证据
Quasiparticle Interference Evidence of the Topological Fermi Arc States in Chiral Fermionic Semimetal CoSi
论文作者
论文摘要
固态中的手性费米斯特征“费米弧”状态，连接了散装手性节点的表面投影。表面费米弧是非平凡散装拓扑的标志。理论上在COSI中提出了非常规的手性费米子。在这里，我们使用扫描隧道显微镜 /光谱法研究了COSI单晶各种终止处的准粒子干扰。观察到的表面状态表现出手性费米的原始特征。这些位于（001）和（011）上，但不存在于（111）表面，具有pi旋转对称性，螺旋带有能量，并且分散在〜-200至〜+400 mV的广泛能量范围内。由于高能和高空间分辨率，可以确定自旋轨道耦合诱导的分裂高达〜80 mV。我们的观察结果通过密度功能理论证实，并提供了有力的证据，表明COSI拥有非常规的手性费米子和广泛的费米弧状态。
Chiral fermions in solid state feature "Fermi arc" states, connecting the surface projections of the bulk chiral nodes. The surface Fermi arc is a signature of nontrivial bulk topology. Unconventional chiral fermions with an extensive Fermi arc traversing the whole Brillouin zone have been theoretically proposed in CoSi. Here, we use scanning tunneling microscopy / spectroscopy to investigate quasiparticle interference at various terminations of a CoSi single crystal. The observed surface states exhibit chiral fermion-originated characteristics. These reside on (001) and (011) but not (111) surfaces with pi-rotation symmetry, spiral with energy, and disperse in a wide energy range from ~-200 to ~+400 mV. Owing to the high-energy and high-space resolution, a spin-orbit coupling-induced splitting of up to ~80 mV is identified. Our observations are corroborated by density functional theory and provide strong evidence that CoSi hosts the unconventional chiral fermions and the extensive Fermi arc states.
