Experimental evidence of hourglass fermion in the candidate nonsymmorphic topological insulator KHgSb

Junzhang Ma, Changjiang Yi, Baiqing Lv, Zhijun Wang, Simin Nie, Le Wang, Lingyuan Kong, Yaobo Huang, Pierre Richard, Peng Zhang, Koichiro Yaji, Kenta Kuroda, Shik Shin, Hongming Weng, Bogdan Andrei Bernevig, Youguo Shi, Tian Qian, Hong Ding

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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.

Original languageEnglish (US)
Article numbere1602415
JournalScience Advances
Issue number5
StatePublished - May 2017

All Science Journal Classification (ASJC) codes

  • General


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