Extended Data Fig. 2: Variation of Ni-doping concentration in RhSi.
From: Tunable topologically driven Fermi arc van Hove singularities
a, Surface-sensitive ARPES measured Fermi surface map (E = 0 eV) of 9% Ni-doped RhSi. b, Constant energy contour at energy E = − 0.22 eV for 9% Ni-doped RhSi. Guides for the eye (black dashed lines) track the helicoid arcs. c, Bulk-sensitive ARPES measured energy-momentum cut along the \(\bar{{{\Gamma }}}\)-pocket of RhSi (left panel) and 5% Ni-doped RhSi (right panel). d, Fermi surface map of 5% Ni-doped RhSi. e, f, Energy-momentum cuts along \(\bar{{{{\rm{Y}}}}}\) for two orthogonal directions: \(\bar{{{{\rm{Y}}}}}-\bar{{{{\rm{M}}}}}\) (green dashed line: panel e) and \(\bar{{{{\rm{Y}}}}}-\bar{{{\Gamma }}}\) (purple dashed line: panel f). The (001) surface BZ is annotated by black dashed lines. g, ARPES measured constant-energy contours of Ni0.05Rh0.95Si. The helicoid arcs near the \(\bar{{{{\rm{M}}}}}-\bar{{{{\rm{Y}}}}}-\bar{{{{\rm{M}}}}}\) line approach each other with increasing energy and are on track to touch at the \(\bar{{{{\rm{Y}}}}}\)-point, indicated by the orange dashed parabola. A parabolic function fitted to the chiral modes near the Fermi level provides a guide for the eye to visualize the saddle-shape dispersion bottom band (orange dashed line). The fit suggests that the type-I helicoid arc van Hove energy is about + 0.073 eV above the Fermi level of Ni0.05Rh0.95Si.
