title: Anomalies of a topologically ordered surface.
abstract: Bulk insulators with strong spin orbit coupling exhibit metallic surface states possessing topological order protected by the time reversal symmetry. However, experiments show vulnerability of topological states to aging and impurities. Different studies show contrasting behavior of the Dirac states along with plethora of anomalies, which has become an outstanding problem in material science. Here, we probe the electronic structure of Bi(2)Se(3) employing high resolution photoemission spectroscopy and discover the dependence of the behavior of Dirac particles on surface terminations. The Dirac cone apex appears at different binding energies and exhibits contrasting shift on Bi and Se terminated surfaces with complex time dependence emerging from subtle adsorbed oxygen-surface atom interactions. These results uncover the surface states behavior of real systems and the dichotomy of topological and normal surface states important for device fabrication as well as realization of novel physics such as Majorana Fermions, magnetic monopole, etc.
authors.affiliation: Department of Condensed Matter Physics and Materials' Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai - 400 005, India.
authors.forename: Deepnarayan
authors.initials: D
authors.lastname: Biswas
authors.affiliation: Department of Condensed Matter Physics and Materials' Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai - 400 005, India.
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Thakur
authors.affiliation: Department of Condensed Matter Physics and Materials' Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai - 400 005, India.
authors.forename: Khadiza
authors.initials: K
authors.lastname: Ali
authors.affiliation: Department of Physics, University of Warwick, Coventry, CV4 7AL, UK.
authors.forename: Geetha
authors.initials: G
authors.lastname: Balakrishnan
authors.affiliation: Department of Condensed Matter Physics and Materials' Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai - 400 005, India.
authors.forename: Kalobaran
authors.initials: K
authors.lastname: Maiti