Presentation Information
[2I05]Evolution of the surface electronic structure of Bi2Se3 by hydrogen exposure
*Yusei Ohashi1, Makoto Hashimoto3, Katsuyuki Fukutani1,2 (1. Institute of Industrial Science, the University of Tokyo, 2. Advanced Science Research Center, Japan Atomic Energy Agency, 3. Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory)
Bi2Se3 is a three-dimensional topological insulator with spin–momentum–locked surface states that are stable against nonmagnetic perturbations but strongly affected by surface adsorption. Earlier studies reported that hydrogen exposure removes Se atoms and induces Bi(111) bilayer formation, yet the detailed evolution of the surface states with dose remained unclear. In this work, we systematically examined hydrogen-dose-dependent changes in Bi2Se3 using ARPES. We observed an initial electron doping effect, seen as a downward shift of the Dirac point, followed by a gradual suppression of the topological surface states. At higher exposure levels, the original bands disappeared and new dispersions characteristic of Bi bilayers emerged. Further annealing enhanced these bilayer-derived features, suggesting surface restructuring associated with Se desorption. These results clarify how hydrogen progressively modifies the Bi2Se3 surface from doping and suppression of the topological state to the emergence of Bi(111) bilayers and provide a basis for controlled tuning of surface electronic properties in topological and spintronic applications.