Figure 3
Direct observation of the overlap of the VBM and the DP.
(a) Three-dimensional illustration of the Dirac cone in QAH system. (b) CEC map at the energy of the DP. The solid yellow lines across the Brillouin zone indicate the cut directions of the band dispersion spectra in (c) and Fig. S4. (c) High-resolution band dispersion along cut 2. Two symmetric branches of BVB centered at k = 0 cross the ED. Photon energy of 20.5 eV is chosen to highlight the VB. As shown in (b), the BVB in cut 2 connects the petals of the flower-shaped CECs with different energies. (d) Complementary approaches to the bulk localization problem: Anderson localization of the BVB with strong spin orbit coupling can lead to an insulating 2D bulk at low temperatures only if the sample lies in the unitary symmetry class. Conversely, the internal magnetic field of V moment can quantize electron motion in the BVB to insulate the thin film bulk. The QAH sample hosts counter-propagating chiral edge states at the thin film edges.
