(color online) Surface potassium doping results in ZrSiS. (a) Stacking plots of constant-energy contours in broader binding energy range in the K-doped sample. (b) Side-by-side comparison of (i) pristine and (ii) K-dosed data on the Fermi surface where we can easily distinguish SSs from the BSs. (c) Side-by-side comparison of the high symmetry cut along – – direction in the (i) pristine and (ii) K-dosed sample where the SSs are labelled. (d) Side-by-side comparison of the high symmetry cuts along – – direction in the (i) pristine and (ii) K-dosed sample where the SSs and BSs are labelled.