Extended Data Fig. 7: Photo-induced band bending effect.
From: High-harmonic generation from topological surface states
Under laser light illumination, photo-induced carriers are generated near the surface. Due to the band bending (gray dashed line) already existed, the electrons (e, blue solid circles) are accumulated near the surface attracted by the electrostatic potential, while the holes (h, blue open circles) are drift into the bulk, thus result in an intensified band bending (gray solid line). The red and green curves on the right-hand side show the band structure of the topological surface states (TSS) and Rashba-split two-dimensional electron gas (2DEG) states, the black arrows denote the spin polarization. EF: Fermi surface, BVB: bulk valence band, BCB: bulk conduction band.
