By compressing elemental silicon and hydrogen in a diamond anvil cell, we have synthesized polymeric silicon tetrahydride (SiH4) at 124 GPa and 300 K. In situ synchrotron x-ray diffraction reveals that the compound forms the insulating I41/a structure previously proposed from ab initio calculations for the high-pressure phase of silane. From a series of high-pressure experiments at room and low temperature on silane itself, we find that its tetrahedral molecules break up, while silane undergoes pressure-induced amorphization at pressures above 60 GPa, recrystallizing at 90 GPa into the polymeric crystal structures.
Physical Review Letters
- Pub Date:
- March 2011
- High-pressure effects in solids and liquids;
- X-ray diffraction and scattering;
- General studies of phase transitions;
- Infrared and Raman spectra