Logo of Phonon GeO_2

Z.Lodziana, K.Parlinski and J.Hafner,
Ab initio studies of high-pressure transformations in GeO_2
Phys.Rev. B 63, 134106 (2001).

Crystal: Germanium dioxide GeO_2
Software: Ab initio VASP ver.4.3.3
Space group: rutile, tetragonal, P4_2/mnn (D_4h^14) (Z=2)
Lattice constants: a=4.3838, c=2.8637 angst.
Supercell: 2x2x2 and 1x1x8.
Pseudopotentials: ultrasoft of Vanderbilt.
k-points: 2x2x2 and 4x4x1, respectively.
Soft mode found under pressure. It induces ferroelastic phase transition to orthorhombic CsCl_2-type structure.

Phonon dispersion relations of germanium dioxide GeO_2:

Phonon Dispersion Curves of GeO_2