Fig. 3
From: Observation of two superconducting domes under pressure in tetragonal FeS
a The in situ powder synchrotron XRD patterns of FeS under various pressures at room temperature. The characteristic peaks of two structures are marked to show the evolution with increasing pressure. b, c Net-like hexagonal structure (P-62c) and layered tetragonal structure (P4/nmm) of FeS. d–f Pressure dependence of the lattice parameters a, c, as well as unit cell volume. The red and blue solid circles represent the tetragonal and hexagonal phase, respectively. A two-phase coexisting region is highlighted from 7.2 to 9.2 GPa
