Observation of Dirac-like surface state bands on the top surface of BiSe

Abstract

Two quintuple layers of strong topological insulator Bi2Se3 are coupled by a Bi bilayer in BiSe crystal. We investigated its electronic structure using angle resolved photoelectron spectroscopy to study its topological nature. Dirac like linearly dispersive surface state bands are observed on the 001 surface of BiSe and Sb doped BiSe, similar to Bi2Se3. Moreover, the lower part of the SSBs buries deep in the bulk valence band. Overlap region between the SSBs and BVB is large in Sb doped system and the SSBs deviate from the Dirac like linear dispersion in this region. These results highlight the role of interlayer coupling between the Bi bilayer and the Bi2Se3 QLs. Furthermore, we observed a large intensity imbalance in the SSBs located at the positive and negative k parallel directions. This asymmetry pattern gradually reverses as the excitation energy scans from low 14eV to high 34eV value. However, we did not observe signal of surface magnetization resulting from the intensity imbalance in SSBs due to hole-generated uncompensated spin accumulation in the photoexcitation process. The main reason for this could be the faster relaxation process for photo hole due to the presence of the Bi bilayer between the adjacent Bi2Se3 QLs. The observed photon energy dependent intensity variation could be a signature of the mixing between the spin and the orbit texture of the SSBs.

References in corpus (15)

• Topological Insulators
• Topological insulators and superconductors
• Topological Insulators with Inversion Symmetry
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• First direct observation of Spin-textures in Topological Insulators : Spin-resolved ARPES as a probe of topological quantum spin Hall effect and Berry's phase
• Multiple topological states in iron-based superconductors
• Unexpected mass acquisition of Dirac fermions at the quantum phase transition of a topological insulator
• The strong side of weak topological insulators
• Stacked topological insulator built from bismuth-based graphene sheet analogues
• Photoelectron spin-flipping and texture manipulation in a topological insulator
• Discovery of switchable weak topological insulator state in quasi-one-dimensional bismuth iodide
• Orbital-Selective Spin Texture and its Manipulation in a Topological Insulator
• Signatures of Topological Superconductivity in Bulk Insulating Topological Insulator BiSbTe${}_{1.25}$Se${}_{1.75}$ in Proximity with Superconducting NbSe${}_2$
• Band Structure of Topological Insulator BiSbTe1.25Se1.75
• Synchrotron radiation induced magnetization in magnetically-doped and pristine topological insulators