Bulk and surface electronic structure of trigonal structured PtBi2   studied by angle-resolved photoemission spectroscopy
  PtBi2 with a layered trigonal crystal structure was recently reported to exhibit an unconventional large linear magnetoresistance, while the mechanism involved is still elusive. Using high resolution angle-resolved photoemission spectroscopy, we present a systematic study on its bulk and surface electronic structure. Through careful comparison with first-principle calculations, our experiment distinguishes the low-lying bulk bands from entangled surface states, allowing the estimation of the real stoichiometry of samples. We find significant electron doping in PtBi2, implying a substantial Bi deficiency induced disorder therein. We discover a Dirac-cone-like surface state on the boundary of the Brillouin zone, which is identified as an accidental Dirac band without topological protection. Our findings exclude quantum-limit-induced linear band dispersion as the cause of the unconventional large linear magnetoresistance. 
Q. Yao, Y. P. Du, X. J. Yang, Y. Zheng, D. F. Xu, X. H. Niu, H. F.   Yang, P. Dudin, T. K. Kim, M. Hoesch, I. Vobornik, Z. -...
cond-mat.str-el cond-mat.mtrl-sci cond-mat.supr-con