Fig. 2: Observation of massive Dirac-cone bands in the AF phase.

a Schematic FS of NdBi projected onto the surface BZ. e1 and e2 (blue curves) represent electron pockets elongated along k_x and k_y, respectively, and are located at different X points in the bulk BZ. h1 and h2 (red curves) represent inner and outer hole pockets, respectively. b FS mapping around the \(\bar{\Gamma }\) point in the AF phase (T = 5 K) measured at hν = 60 eV. c, d ARPES intensity around the \(\bar{\Gamma }\) point in the PM phase (T = 30 K) and the AF phase (T = 5 K), respectively, measured at hν = 75 eV. e EDCs at the \(\bar{\Gamma }\) point at T = 5 K (orange curve) and 30 K (black curve). Dashed lines are a guide for the eyes to trace the upper and lower D1 (D1U and D1L). f Temperature dependence of ARPES intensity at the \(\bar{\Gamma }\) point. Dashed curves are a guide for the eyes to highlight the gap opening across T_N for D1. g–i Same as (b–d) but around the \(\bar{{{{{{\rm{M}}}}}}}\) point obtained at hν = 60 eV. Dashed curves in (h, i) are a guide for the eyes to trace the band dispersion of D2 and D3 as well as their lower and upper branches. j, k Same as (e, f) but measured at the \(\bar{{{{{{\rm{M}}}}}}}\) point. Dashed curves in (k) are a guide for the eyes to highlight the gap opening across T_N for D2 and D3.