The ARPES measurements of the (111) surface states of SnTe-class materials. (a) Near-E_F ARPES intensity of SnTe measured along several cuts around the point. Blue arrow indicates the top of the band.^[56] (b) ARPES intensity in the vicinity of the point for SnTe, Pb_0.25Sn_0.75Te, Pb_0.7Sn_0.3Te, and PbTe, respectively.^[61] (c) Photon energy dependent ARPES measurements around the point on a (111) oriented Pb_1−xSn_xSe film. The bulk band is strongly dependent on the photon energy, while the position of the Dirac-like dispersion is unchanged when varying the photon energy, indicating the nature of surface states. However, its intensity is strongly modulated with the photon energy.^[62]