@article{0087698a25e44221a00b1eaffbd5ed53,
title = "Experimental evidence of hourglass fermion in the candidate nonsymmorphic topological insulator KHgSb",
abstract = "Topological insulators (TIs) host novel states of quantum matter characterized by nontrivial conducting boundary states connecting valence and conduction bulk bands. All TIs discovered experimentally so far rely on either time-reversal or mirror crystal symmorphic symmetry to protect massless Dirac-like boundary states. Several materials were recently proposed to be TIs with nonsymmorphic symmetry, where a glide mirror protects exotic surface fermions with hourglass-shaped dispersion. However, an experimental confirmation of this new fermion is missing. Using angle-resolved photoemission spectroscopy, we provide experimental evidence of hourglass fermions on the (010) surface of crystalline KHgSb, whereas the (001) surface has no boundary state, in agreement with first-principles calculations. Our study will stimulate further research activities of topological properties of nonsymmorphic materials.",
author = "Junzhang Ma and Changjiang Yi and Baiqing Lv and Zhijun Wang and Simin Nie and Le Wang and Lingyuan Kong and Yaobo Huang and Pierre Richard and Peng Zhang and Koichiro Yaji and Kenta Kuroda and Shik Shin and Hongming Weng and Bernevig, {Bogdan Andrei} and Youguo Shi and Tian Qian and Hong Ding",
note = "Funding Information: We acknowledge W. Yi, S.-F. Jin, and Z.-L. Li for refinements of the powder XRD data, as well as C. Fang, X. Dai, T.-T. Zhang, and D. Chen for valuable discussions. Funding: This work was supported by the Ministry of Science and Technology of China (2016YFA0300600, 2016YFA0401000, 2015CB921300, and 2013CB921700), the National Natural Science Foundation of China (11622435, 11474340, 11422428, 11274367, 11474330, 11504117, 11234014, 11274362, and 11674371), and the Chinese Academy of Sciences (CAS) (XDB07000000). Z.W. and B.A.B. were also supported by the Department of Energy (DE-SC0016239), NSF Early Concept Grants for Exploratory Research Award (NOA-AWD1004957), Simons Investigator Award (ONR-N00014-14-1-0330), Army Research Office Multidisciplinary University Research Initiative (W911NF-12-1-0461), NSF Materials Research Science and Engineering Center (DMR-1420541), Packard Foundation, and Schmidt Fund for Innovative Research. Y.H. acknowledges funding from the CAS Pioneer Hundred Talents Program (type C). Publisher Copyright: {\textcopyright} The Authors, some rights reserved.",
year = "2017",
month = may,
doi = "10.1126/sciadv.1602415",
language = "English (US)",
volume = "3",
journal = "Science Advances",
issn = "2375-2548",
publisher = "American Association for the Advancement of Science",
number = "5",
}