Observation of a nodal chain with Dirac surface states in TiB2 | |
Article | |
关键词: WANNIER FUNCTIONS; SEMIMETAL; DISCOVERY; FERMIONS; | |
DOI : 10.1103/PhysRevB.97.201107 | |
来源: SCIE |
【 摘 要 】
Topological nodal-line semimetals (TNLSMs) are characterized by symmetry-protected band crossings extending along one-dimensional lines in momentum space. The nodal lines exhibit a variety of possible configurations, such as nodal ring, nodal link, nodal chain, and nodal knot. Here, using angle-resolved photoemission spectroscopy, we observe nodal rings on the orthogonal k(z) = 0 and k(x) = 0 planes of the Brillouin zone in TiB2. The nodal rings connect with each other on the intersecting line Gamma-Kof the orthogonal planes forming a remarkable nodal-chain structure. Furthermore, we observe surface states (SSs) on the (001) cleaved surface, which are consistent with the calculated SSs considering the contribution from both Ti and B terminations. The calculated SSs have novel Dirac-cone-like band structures, which are distinct from the usual drumhead SSs with a single flatband proposed in other TNLSMs.
【 授权许可】
Free