Extended Data Fig. 4: Dependence of the pseudogap on photon energy and samples.
From: Pseudogap in a crystalline insulator doped by disordered metals
a, Photon-energy dependence of ARPES data taken from black phosphorus whose surface is doped by K at nd = 1.8 × 1014 cm−2. A pseudogap of 30 meV at this nd is robustly observed for a photon energy of 106–125 eV (red arrow) in contrast to the C2 band that crosses EF (blue arrow). b, c, Sample dependence of ARPES data taken from black phosphorus doped by Na at nd = 1.7 × 1014 cm−2 (b) and K at nd = 1.0 × 1014 cm−2 (c). The pseudogap of 235 meV for Na and 65 meV for K is observed without exception for all of the samples.
