High-density amorphous phase of silicon carbide obtained under large plastic shear and high pressure

In situ x-ray diffraction study of the hexagonal 6H SiC under pressure and shear in rotational diamond anvil cell is performed that reveals phase transformation to the new high-density amorphous (hda) phase SiC. In contrast to known low-density amorphous SiC, hda-SiC is promoted by pressure and unstable under pressure release. The critical combination of pressure similar to 30 GPa and rotation of an anvil of 2160 degrees that causes disordering is determined.