In situ XAFS Investigation on Zincblende ZnS up to 31.7 GPa

Abstract

In situ high-pressure x-ray absorption fine structure (EXAFS) measurements on the Zn K-edge in zincblende ZnS are performed up to 31.7 GPa at room temperature using a synchrotron radiation x-ray re-focused by a polycapillary half-lens in the classic energy-scanning transmission mode. The present XAFS data illustrate that ZnS undergoes a phase transition from zincblende F4̄3m to rocksalt Fm3̄m at 16.9 GPa, accompanied by the increase of the first shell coordination number of the absorption zinc atoms and the unit-cell volume collapse of ∼14%. The isothermal equation of state of the F4̄3m ZnS is well presented by the third-order Birch—Murnaghan equation of state with V0 = 158.6 ± 0.8 Å3, B0 = 87 ± 5 GPa and B′0 = 4 (fixed). The high-pressure behavior of ZnS from the XAFS spectra is consistent with the previous high-pressure XRD results. In addition, the present experimental method demonstrates that the large divergent x-ray micro-beam induced by a polycapillary half-lens can suppress effectively the glitches from single crystal diamond anvil and improve significantly the quality of the XAFS data, which will shed light on the high-pressure XAFS applications.