Transient Surface Photoemission Involving Nonlinear Surface Sheet Polarization Developed on the Doped Bi2Se3 Topological Insulator
Abstract
Time- and angle-resolved photoemission spectroscopy is performed on the doped Bi2Se3 topological insulator. We observe unusual variation in the efficiency of photoemission from femto-to-picosecond non-equilibrium particularly when two-dimensional electron gas (2DEG) states are developed on surface, while the surface confinement potential is virtually unchanged. The results indicate that a surface sheet polarization, which is induced nonlinearly by both the photon field and inversion-symmetry-breaking field, grows in magnitude as the 2DEG states become pronounced and opens a so-called surface photoemission channel, div A, that can be varied transiently. Matrix element effects investigated by linearly-polarized angle-resolved photoemission also supports the presence of div A. The asymmetric charge distribution developed around vacuum-surface interface is considered as a key to understand and control Rashba splitting of the 2DEG states.
This research is partially supported by KAKENHI(23740256) and by the JSPS through its ``FIRST Program''- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2013
- Bibcode:
- 2013APS..MARU13003I