In situx-ray diffraction study of silicon at pressures up to 15.5 GPa and temperatures up to 1073 K

Abstract

In situ x-ray diffraction measurements of silicon were conducted in the pressure range 6–15.5 GPa and at temperatures up to 1073 K. The results were used to improve the phase diagram for silicon. The pressure range where the ${\mathrm{Si}}_{\mathrm{II}}$ phase is stable in the temperature interval 293–973 K was found. The positions of the ${\mathrm{Si}}_{\mathrm{I}}-{\mathrm{Si}}_{\mathrm{II}},$ ${\mathrm{Si}}_{\mathrm{II}}-{\mathrm{Si}}_{\mathrm{XI}},$ ${\mathrm{Si}}_{\mathrm{XI}}-{\mathrm{Si}}_{\mathrm{V}}$ equilibrium lines and the ${\mathrm{Si}}_{\mathrm{I}}-{\mathrm{Si}}_{\mathrm{II}}-{\mathrm{Si}}_{\mathrm{L}},$ ${\mathrm{Si}}_{\mathrm{II}}-{\mathrm{Si}}_{\mathrm{XI}}-{\mathrm{Si}}_{\mathrm{L}},$ ${\mathrm{Si}}_{\mathrm{XI}}-{\mathrm{Si}}_{\mathrm{V}}-{\mathrm{Si}}_{\mathrm{L}}$ triple points were determined.