论文标题
Co $ _3 $ sn $ _2 $ S $ _2 $的拓扑Weyl Loop的签名
Signatures of a topological Weyl loop in Co$_3$Sn$_2$S$_2$
论文作者
论文摘要
量子磁铁中物质的新拓扑阶段的搜索已成为凝结物理学的前沿。在这里,我们使用最先进的角度分辨光发射光谱(ARPES)来研究其铁磁阶段的CO $ _3 $ sn $ _2 $ _2 $ s $ _2 $的单晶。我们首次报告拓扑Weyl环的签名。从基本的对称考虑因素来看,如果旋转轨道耦合(SOC)严格为零,但可能会在有限的SOC下与可能的Weyl点相处,则该磁性Weyl环将是无间隙的。我们指出,迄今为止,高分辨率ARPES的结果无法明确解决沿Weyl环路的任何地方的SOC间隙,从而打开了CO $ _3 $ SN $ _2 $ _2 $ _2 $ S $ _2 $ host零weyl点或一些非零点Weyl点的可能性。在我们的样品表面上,我们进一步观察了可能的费米弧,但我们无法使用已建立的计数标准清楚地验证其拓扑性质。结果,我们认为,从光发射光谱的角度来看,co $ _3 $ sn $ _2 $ _2 $ s $ _2 $的Weyl点和费米弧的存在仍然模棱两可。我们的结果对正在进行的CO $ _3 $ SN $ _2 $ S $ _2 $和其他拓扑磁铁的调查具有影响。
The search for novel topological phases of matter in quantum magnets has emerged as a frontier of condensed matter physics. Here we use state-of-the-art angle-resolved photoemission spectroscopy (ARPES) to investigate single crystals of Co$_3$Sn$_2$S$_2$ in its ferromagnetic phase. We report for the first time signatures of a topological Weyl loop. From fundamental symmetry considerations, this magnetic Weyl loop is expected to be gapless if spin-orbit coupling (SOC) is strictly zero but gapped, with possible Weyl points, under finite SOC. We point out that high-resolution ARPES results to date cannot unambiguously resolve the SOC gap anywhere along the Weyl loop, leaving open the possibility that Co$_3$Sn$_2$S$_2$ hosts zero Weyl points or some non-zero number of Weyl points. On the surface of our samples, we further observe a possible Fermi arc, but we are unable to clearly verify its topological nature using the established counting criteria. As a result, we argue that from the point of view of photoemission spectroscopy the presence of Weyl points and Fermi arcs in Co$_3$Sn$_2$S$_2$ remains ambiguous. Our results have implications for ongoing investigations of Co$_3$Sn$_2$S$_2$ and other topological magnets.