Phase transition studies of germanium to 1.25 Mbar
Abstract
New phase transitions in Ge were observed by energy-dispersive x-ray diffraction techniques for pressures up to 125 GPa (1.25 Mbar) as follows: the β-Sn structure to the simple hexagonal (sh) phase at 75+/-3 GPa and to the double hexagonal close-packed structure (dhcp) at 102+/-5 GPa. These are the highest pressures for which a crystalline structure change has been directly observed in any material by x-ray diffraction. Total-energy pseudopotential calculations predict 84+/-10 GPa for the β-Sn to sh phase transition and 105+/-21 GPa for sh to hcp (not dhcp) transition. The role of 3d core electrons in increasing the transformation pressures in Ge, as compared to Si, is emphasized.
- Publication:
-
Physical Review Letters
- Pub Date:
- May 1986
- DOI:
- 10.1103/PhysRevLett.56.1944
- Bibcode:
- 1986PhRvL..56.1944V
- Keywords:
-
- Germanium;
- Hexagonal Cells;
- Phase Transformations;
- Pseudopotentials;
- Transition Pressure;
- Body Centered Cubic Lattices;
- Close Packed Lattices;
- Crystal Structure;
- Electron States;
- High Pressure;
- X Ray Diffraction;
- Solid-State Physics;
- 64.70.Kb;
- 62.50.+p;
- 64.30.+t;
- Solid-solid transitions;
- High-pressure and shock wave effects in solids and liquids;
- Equations of state of specific substances