Compressional behavior of solid NeHe2 up to 90 GPa

NeHe₂ was compressed to about 90 GPa using a diamond anvil cell technique. The crystal structure was confirmed to be stable with hexagonal symmetry in the investigated pressure range and its p-V equation of state was determined by angular dispersive x-ray diffraction with synchrotron radiation. With the help of ab initio calculations, the compressibility and inter-atomic distances of NeHe₂ were compared with those of a helium and neon mixture of the same composition. This study shows that the bulk modulus of NeHe₂ is between those of neon and helium and that linear compressibilities of the inter-atomic distances are different from those of the elementary solids. This material can be a pressure-transmitting medium, providing both a large sample space and good quasi-hydrostatic conditions.