title: Angle-resolved photoemission spectroscopy study on the surface states of the correlated topological insulator YbB6.
abstract: YbB6 is recently predicted to be a moderately correlated topological insulator, which provides a playground to explore the interplay between correlation and topological properties. With angle-resolved photoemission spectroscopy, we directly observed almost linearly dispersive bands around the time-reversal invariant momenta and with negligible kz dependence, consistent with odd number of surface states crossing the Fermi level in a Z2 topological insulator. Circular dichroism photoemission spectra suggest that these in-gap states possess chirality of orbital angular momentum, which is related to the chiral spin texture, further indicative of their topological nature. The observed insulating gap of YbB6 is about 100 meV, larger than that found by theoretical calculations. Our results present strong evidence that YbB6 is a correlated topological insulator and provide a foundation for further studies of this promising material.
authors.affiliation: 1] State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China [2].
authors.forename: M
authors.initials: M
authors.lastname: Xia
authors.affiliation: 1] State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China [2].
authors.forename: J
authors.initials: J
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China.
authors.forename: Z R
authors.initials: ZR
authors.lastname: Ye
authors.affiliation: Department of Physics and Applied Physics, Stanford University, Stanford, California, 94305, USA.
authors.forename: Y H
authors.initials: YH
authors.lastname: Wang
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Physics and Applied Physics, Stanford University, Stanford, California, 94305, USA.
authors.forename: S D
authors.initials: SD
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China.
authors.forename: X H
authors.initials: XH
authors.lastname: Niu
authors.affiliation: State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China.
authors.forename: D F
authors.initials: DF
authors.lastname: Xu
authors.affiliation: Department of Physics and Hefei National Laboratory for Physical Science at Microscale, University of Science and Technology of China, Hefei 230026, China.
authors.forename: F
authors.initials: F
authors.lastname: Chen
authors.affiliation: Department of Physics and Hefei National Laboratory for Physical Science at Microscale, University of Science and Technology of China, Hefei 230026, China.
authors.forename: X H
authors.initials: XH
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China.
authors.forename: B P
authors.initials: BP
authors.lastname: Xie
authors.affiliation: State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China.
authors.forename: T
authors.initials: T
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China.
authors.forename: D L
authors.initials: DL
authors.lastname: Feng
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