Fig. 4: Dirac surface states on the (010) surface.
From: Discovery of \({\hat{\boldsymbol{C}}}_2\) rotation anomaly in topological crystalline insulator SrPb
a Schematic band structures of SrPb showing two surface Dirac cones protected by \(\hat C_{2y}\) rotational symmetry. b Schematic of tilted surface Dirac cones, showing dispersions of Dirac-like band crossings along and perpendicular to the tilt direction. c Near-EF band dispersions along \({\bar{{\Gamma }}} \,-\, \bar X\) extracted from the ARPES data collected at different photon energies and temperatures. d ARPES intensity plot along \({\bar{{\Gamma }}} \,-\, \bar X\) measured with \(h\nu \,=\,\) 20 eV at 200 K. e Momentum distribution curves of the data in (d). f ARPES intensity plot along \({\bar{{\Gamma }}} \,-\, \bar X\) measured with \(h\nu \,=\,\) 30 eV at 200 K. g 2D curvature intensity plot of the data in (f), showing two surface bands cross each other forming a surface Dirac point (SDP). The method of 2D curvature was developed in45. h Calculated band structures along \({\bar{{\Gamma }}} \,-\, \bar X\) of a slab with a thickness of five unit cells along the [010] direction for termination A, whose cleavage position is indicated as a yellow plane in Fig. 1a. The size of red dots scales the contribution from the outmost two SrPb layers. The Fermi level of the calculated bands is shifted down by 0.14 eV. i, j ARPES intensity plots and corresponding 2D curvature intensity plots along the cuts perpendicular to \({\bar{{\Gamma }}} \,-\, \bar X\), whose momentum locations are indicated in Fig. 3d. The data in (i) were collected with hν = 30 eV at 200 K. The ARPES data in Fig. 4 are divided by the Fermi–Dirac distribution function.
