Extended Data Fig. 8: Temperature-dependent linear dichroism in the Dirac cone photoemission intensity.

a, Dispersion of MnBi₂Te₄(0001) measured at 18 K with a photon energy of 21.5 eV and p-polarized light along the \(\bar{{\rm{K}}}\mbox{--}\bar{\Gamma }\mbox{--}\bar{{\rm{K}}}\) direction. b, Momentum distribution curves representation of the data acquired at 18 K (blue) and 80 K (red). c, Linear dichroism (I_right − I_left), where I_right and I_left are the intensities of the right and left branches of the upper and lower cone corresponding to positive and negative k_∥, respectively. The measurements were performed on D samples. d, Upper part of the MnBi₂Te₄(0001) gapped Dirac cone as calculated ab initio. The size of the coloured circles reflects the value and sign of the spin vector Cartesian projections, with red (blue) corresponding to the positive (negative) s_y components (perpendicular to k_z), and yellow (cyan) to the out-of-plane components +s_z (−s_z). e, As in d, but with the size of the purple circles reflecting the weight of the p_x orbitals of all Bi and Te atoms of the topmost septuple-layer block at each k_∥. Note that in d, e the bulk-like bands of the slab are omitted. The magnetic moment of the topmost Mn layer points towards vacuum, but in Fig. 1e and Extended Data Fig. 6 it points in the opposite direction. f, The weight of the s, p_x, p_y and p_z orbitals of all Bi and Te atoms of the topmost septuple-layer block for the left (triangles) and right (squares) branches as a function of energy. See Methods for more information on the dichroic ARPES measurements.