Time-resolved Raman spectroscopy study of rapid compressed silicon and its potential as a Raman pressure scale in a dynamic diamond anvil cell

The nature of the nonequilibrium states of materials upon rapid compression/decompression processes in the intermediate regime, between static and shock compression, is an emerging field of high pressure research. Rapid compression experiments were performed to examine the structural response of silicon (Si) up to 11 GPa and over compression rates ranging from 0.011 to 0.325 GPa/s, using a piezo-driven dynamic diamond anvil cell (dDAC) coupled with time-resolved Raman spectroscopy. The observed structural stability and the remarkable consistency in the pressure-dependent Raman shift of the diamond cubic Si (Si-I) showed its high potential as a Raman pressure scale for compression rate below 0.325 GPa/s. The validity of the derived Si scale was verified by in situ continuously monitoring pressure of two rapid compressed samples, that is, gypsum and ZnO. Results indicated that pressures determined using Si were in good agreement with those estimated from the ruby scale. Success in pressure calibration with Si, during time-resolved Raman spectroscopy measurements of material under rapid compression using a dDAC, will greatly simplify the required hardware system in home-laboratory and may also help in reaching a higher signal-to-noise in Raman measurement on a short time scale.