Evidence for the R8 phase of germanium

Phys Rev Lett. 2013 Feb 22;110(8):085502. doi: 10.1103/PhysRevLett.110.085502. Epub 2013 Feb 20.

Abstract

The formation of R8 germanium is reported. The β-Sn phase is first induced by the indentation of amorphous germanium (a-Ge) and the resultant phases on pressure release are characterized by Raman scattering. The expected Raman line frequencies for the various phases of Ge are determined from first-principles calculations using density functional perturbation theory of the zone-center phonons in the diamond, ST12, BC8, and R8 Ge phases. In addition to the R8 phase, traces of BC8 may also be present following pressure release.