Fig. 3

Demonstration of the procedure used to separate QPI from bulk, surface, and joint states. a shows the Fermi surface at −70 meV. Because the Fermi arcs sharply contrast with the bulk states, they are easily separated from the rest of the band structure through intensity thresholding. The gray rectangle shows where a mask is applied to exclude the more intense bulk bands in the center from the threshold. b shows all three QPI components overlaid, with bulk shown in blue, joint shown in green, and surface shown in red. c shows the Fourier transform of a differential conductance map at −35 meV, cropped to the first BZ for comparison to the calculated QPI. The horizontal wing feature matches with the QPI calculated from the Fermi arc surface states. d shows in blue the QPI coming from the bulk states only, with the Fermi arcs removed. e shows the joint QPI which comes from scattering between bulk and surface states. f shows the QPI coming only from the Fermi arc surface states