Fig. 1.

(A and B) Schematic illustrations of the Fermi surface in the nematic and the tetragonal phases (23). Green, red, and blue areas represent the Fermi surface regimes dominated by $d_{xz}$, $d_{yz}$, and $d_{xy}$ orbital characters, respectively. (C) $T$–$x$ phase diagram of FeSe_{1 − x}S_x. (D–G) Temperature dependence of resistivity (thick lines) and its temperature derivative (thin lines) for single crystals of FeSe_{1 − x}S_x for (D) $x=0.08$, (E) x = 0.13, (F) x = 0.16, and (G) x = 0.20. Thick arrows indicate the nematic transition temperatures.