Figure 5

Orbital texture of Au₂Pb. (a) A small window of the cross-section k_z=0.69π (see Figure 6c) of the Brillouin zone, which is near a T-sector. The background colour indicates the energy difference of the conduction band and the valence band (without SOC). Note that there is a dark blue curve on which the conduction band and the valence band are (nearly) degenerate, so the orbital texture will suffer from discontinuity while going across this curve. Based on this consideration, we choose the two green loops, which avoid the degeneracy curve, to calculate the orbital textures. (b) The orbital texture of the phase difference of an Au-d_xy orbital and a Pb-p_x orbital on the valence band. The direction of the arrows indicates the phase difference of different orbital components of the corresponding wavefunction. The winding number of the orbital texture on the inner loop is 0, and the winding number of the orbital texture on the outer loop is −1. (c) The two closed loops partially demonstrate the orbital texture of the effective Hamiltonian (1). The winding number is −1 for the orbital texture on the loop A and is 0 for the loop B, corresponding to the cases of the outer and inner loops in b, respectively.