Figure 4: Photon energy dependence and Dirac-fermion behaviour of the TSS.
From: Observation of unusual topological surface states in half-Heusler compounds LnPtBi (Ln=Lu, Y)
(a) Photoemission intensity plots along the high symmetry 
–
–
direction with photon energies from 50 to 75 eV. Two red dotted lines marked the energy where individual MDC is taken to generate the plots in b,c. (b,c) Intensity plot of the MDCs taken at EF (b) and EF—0.65 eV (c) at different photon energies. The MDC peak positions of all the observed bands are labelled (SS1–SS3 and TSS). (d) Zoom-in intensity plots of the TSS along the 
–
direction and the 
–
direction. Dirac points of the TSS are labelled. Data are taken with 60 eV photons. (e–g) Measured electronic structure of (111) surface of YPtBi. (e) The FS mapping of (111) surface of YPtBi with the hexagonal BZ (overlaid blue lines). The data has been symmetrized according to the crystal symmetry. (f,g) Photoemission intensity (f) and its second-derivative 
plot (g) along the high symmetry 
–
–
direction. Data in e–g are taken with 70 eV photons at T=20 K. SS, topologically trivial metallic surface state due to the dangling bonds on sample surface. TSS, topologically non-trivial surface state.
