Fig. 1. Crystal and electronic structures of Pb(111) thin film on TlBiSe₂.

a Heterostructure consisting of Pb and TlBiSe₂. b Comparison of Brillouin zone between TlBiSe₂ (red) and Pb (green). c Plot of ARPES intensity at E_F as a function of in-plane wave vector (namely, Fermi surface) around the $\overline{\mathrm{\Gamma }\mathrm{M}}$ line for pristine TlBiSe₂, measured with the He-Iα line (hν = 21.218 eV). d ARPES-derived band structure along the $\overline{\mathrm{\Gamma }\mathrm{M}}$ cut for pristine TlBiSe₂. Inset shows the ARPES intensity with enhanced color contrast in the area enclosed by white rectangle. e, f Same as c and d but for 17ML-Pb/TlBiSe₂. g, h Same as e and f but for 17ML-Pb/Si(111). SS, CB, DP, and QWS denote the surface state, conduction band, Dirac point, and quantum well state, respectively. Arrows in d indicate the location of CB and DP. Dashed gray curves are a guide for the eyes to trace the SS and QWSs. Insets to d, f, and h are the LEED patterns of the respective films.