Fig. 4: Band folding to explain the observed QPI features.

a Direct comparison between the normal state JDOS from DFT calculations (left) and QPI (right) at the Fermi level with the QPI features and CDW peak positions marked. The prominent spots seen in the experimental QPI are not observed in the normal state JDOS (pink ellipses). b Fermi surface calculated from DFT. c, Zoomed-in image [dashed box of (b)] showing all the possible hot-spots of the band structure as highlighted by the colored circles. d, Scattering wave-vectors indicated by the 9 independent colored arrows between the hot-spots (black circles). e All experimental scattering wave-vectors (gray dots) within the energy window of [30, −30] meV, superimposed on the 9 independent wave-vectors connecting the hot-spots (colored dots). The arrows indicate the expected energy dispersion from 30 to −30 meV. The experimentally observed QPI dispersion is shown by the pink circles and pink arrows over the same energy range. f Illustration of band folding of states at the hot-spots by one CDW wave-vector (blue arrow). q_s corresponds to a scattering process with an initial state at the hot-spot of the normal state and a final state at the hot-spot arising from band folding, as indicated by the pink arrow. g, Comparison of the dispersion for the experimental QPI (q_s from two different surface terminations with error bars defined) and hot-spot scattering wave-vector (q₁) from theory.