Fig. 3: Weyl fermions and Fermi arcs.
a, b Locations of all Weyl fermions from the top view and side view of the BZ. c ARPES measured Fermi surface (FS) focusing on the W3-W3'-W4 region at 44.5 eV. Loop 1 and Loop 2 are represented by the red and blue circles, respectively. Red and blue markers on the loops indicate actual data points taken before interpolation. Black lines on the loops represent starting and ending positions. The loops are taken clockwise. d Loop cuts taken from (c). (d1) and (d3) are the interpolated data for Loop 1 and Loop 2, respectively. (d2) and (d4) are the corresponding second derivative plots. Green and magenta dashed lines in (d1) and (d3) serve as eye guidance for the upper Fermi arc band and the lower bulk band. e, f Band dispersions measured in the VUV regime (63eV for (e) and 44.5 eV for (f)) related to Weyl fermions W1, W2, W3 and W3' denoted as Cut 1 to 6 in (a), with DFT bulk calculations overlaid. g, h Corresponding ab-initio surface calculations for (e) and (f), respectively. i–l Band dispersions for W1, W2, W3', and W3 measured by soft X-rays at 498 eV. j is taken at the 2nd BZ of the 498 eV cut which actually crosses the W2 kz plane. m Ab-initio surface calculation of constant energy contours taken at the energies of W3', W3, and W4 to show the Fermi arc structure. DFT calculations in the region of W1 and W2 are shifted up by 33 meV, and those calculated in the region of W3 and W3' are shifted up by 120meV. All the ab-initio surface calculations implement Vsurf = 0.15 eV.
