High-pressure EXAFS measurements of crystalline Ge using nanocrystalline diamond anvils

Abstract

High-pressure extended x-ray absorption fine structure (EXAFS) measurements on crystalline Ge demonstrate that the use of nanocrystalline diamond anvils can solve the glitch problem from single crystal diamond anvils and improve the quality of the data. Our results indicate that using nanocrystalline diamond anvils for high-pressure EXAFS research can provide a large enough energy range for structural study up to four coordination shell distances. In particular, we obtained the pressure evolution of mean square relative displacement for the first neighbor shells of crystalline Ge and observed different correlation effects for different coordination shells. The use of nanocrystalline diamond anvils will provide a breakthrough for high-pressure EXAFS study, especially for amorphous compounds in which only limited structural information can be obtained by diffraction techniques.