Fig. 4: The XRD at pressures in MnSe.

a In situ synchrotron XRD patterns of MnSe during compression at room temperature; b the pressure dependence of volume for MnSe. The initial structure is cubic phase, and the intermediate structure retains cubic phase and exhibits the new hexagonal and orthorhombic phases, and the final structure is orthorhombic phase, which could be a new superconducting phase.