Fig. 2

Spin- and angle-resolved photoemission spectroscopy (SARPES) of lowest conduction band (LCB). a Fermi surface sheets (FSs) labeled α and β of LCB measured by using photon energy of 18 eV and the comparison with FSs of DFT calculation (black lines). The constant energy contour (CEC) maps are integrated over a window of ± 20 meV. The dots around X point denote the momentum points where we performed spin measurements, the points 1–3 along cut 1 and the points 4–6 along cut 2 were also marked in b, c. Coordinate axes (P _X , P _Y , P _Z ) denote positive directions of spin vectors. b Band dispersion measured by ARPES (hν = 18 eV) along the cut 1 (Γ–X–Γ line, second derivative). The dashed red and blue lines represent extracted positions from the energy distribution curves (EDCs) used for the estimation of Rashba parameter. c The same as b but along the cut 2 (M–X–M line, second derivative). d Spin-resolved EDCs of P _Y and its spin polarization along cut 1. e The same as d but of P _X along cut 2. The peak positions of spin-up and spin-down states along cut 1 and cut 2 are indicated in b and c by red crosses and blue dots. f The same as d but of P _X , P _Y and P _Z at point 3. g The same as d but of P _X at point 7 and P _Y at point 8