Presence of exotic electronic surface states in LaBi and LaSb

X. H. Niu, D. F. Xu, Y. H. Bai, Q. Song, X. P. Shen, B. P. Xie, Z. Sun, Y. B. Huang, D. C. Peets, and D. L. Feng
Phys. Rev. B 94, 165163 – Published 25 October 2016

Abstract

Extremely high magnetoresistance (XMR) in the lanthanum monopnictides LaX (X=Sb,Bi) has recently attracted interest in these compounds as candidate topological materials. However, their perfect electron-hole compensation provides an alternative explanation, so the possible role of topological surface states requires verification through direct observation. Our angle-resolved photoemission spectroscopy data reveal multiple Dirac-like surface states near the Fermi level in both materials. Intriguingly, we have observed circular dichroism in both surface and near-surface bulk bands. Thus the spin-orbit-coupling-induced orbital and spin angular momentum textures may provide a mechanism to forbid backscattering in zero field, suggesting that surface and near-surface bulk bands may contribute strongly to XMR in LaX. The extremely simple rocksalt structure of these materials and the ease with which high-quality crystals can be prepared suggest that they may be an ideal platform for further investigation of topological matter.

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  • Received 14 July 2016
  • Revised 8 September 2016

DOI:https://doi.org/10.1103/PhysRevB.94.165163

©2016 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

X. H. Niu1,2, D. F. Xu1,2, Y. H. Bai1,2, Q. Song1,2, X. P. Shen1,2, B. P. Xie1,2, Z. Sun2,3, Y. B. Huang4, D. C. Peets1,2,*, and D. L. Feng1,2,†

  • 1State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, People's Republic of China
  • 2Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, People's Republic of China
  • 3National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People's Republic of China
  • 4Shanghai Synchrotron Radiation Facility, Shanghai 201204, People's Republic of China

  • *dpeets@fudan.edu.cn
  • dlfeng@fudan.edu.cn

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Issue

Vol. 94, Iss. 16 — 15 October 2016

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