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Shokri, R.

Coexistence of impurity-induced quasi-one-dimensional electronic structure and topological surface states of Bi2Se3
Journal of Applied Physics 119, (8),pp 085304/1-7 (2016)
Using scanning tunneling spectroscopy (microscopy) (STS, STM) in combination with angle-resolved photoelectron spectroscopy (ARPES), we report on the coexistence of the topological surface state with a long range periodic modulation of the electronic structure on the surface of Bi2Se3 at room temperature. The electronic modulation manifests itself as a two-dimensional commensurate superlattice characterized by stripes running parallel to the surface lattice vectors when the near-surface region of samples are doped with trace amounts of iron or cesium. In both cases, the electronic signature is observed in STM only at energies within the valence band more than 130 meV blow the Dirac point energy (ED). ARPES experiments show the presence of intact Dirac cone, indicating that the electronic stripes do not influence the Diracsurface states. We suggest that the stripe states are the bulk properties of Bi2Se3 induced by trace amounts of cesium and iron impurities residing in bismuth and selenium substitutional sites and/or in the van-der-Waals gap.