Abstract：
During the 2010s, two different types of materials were predicted to host a novel electronic state known as the hourglass fermion. The electronic state exhibits the three-dimensional quantum spin Hall effect and a unique hourglass fermion band dispersion. This study investigated the electronic structure of the layered semi-metallic material Nb3SiTe6 using angle-resolved photoemission spectroscopy, scanning tunneling microscopy, X-ray diffraction, and other technologies. We discovered electronic spin flow in this system and the intriguing hourglass fermion's Dirac nodal lines. Overall, our findings shed light on the system's band structure, provide insights into previous Hall measurements, and hint at the presence of a nodal loop at the zone center of Nb3SiTe6.
Keywords - hourglass fermions, Dirac nodal loop, nonsymmorphic crystals, glide-mirror symmetry, photoemission spectroscopy.