High-density amorphous phase of CdO

An amorphous CdO model is densified up to a theoretical pressure of 200 GPa. A continues phase transformation from a low-density amorphous (LDA) phase to a high-density amorphous (HDA) phase is observed through the simulation. Associated with the phase transformation, the average coordination raises progressively from ~ 5.5 to ~ 7.0. The sevenfold coordination is the most abundant motifs in the HDA state. Therefore its short-range order differs principally from that of the known CdO crystals. Upon pressure release, an amorphous state being intermediate between the LDA structure and the HDA phase is recovered with a mean coordination number of 5.9.