Continuation: Exploration of the Sr-H system towards SrH22 at megabar pressure

The recent claim of the discovery of SrH22, the metal hydride with the highest hydrogen content so far, should provide a system exceptionally close to Ashcroft’s original vision of doped metallic hydrogen, bringing the hydrogen insulator-metal transition down from 400 to 200 GPa.
In this proposal, we aim to continue our exploration of the high-pressure Sr-H system (see HC5668 experimental report). All our DAC loadings are made with gases (hydrogen, Ne, and He) to obtain high-quality samples in terms of homogeneity, chemical integrity, and strain. Unfortunately, we previously faced the extreme reactivity of pure strontium, which hampered any measurement when a too-small Sr chunk was placed in the DACs to reach over the 100 GPa pressure range. Already, interesting data could be obtained below 60 GPa, namely: the compression curve of Sr and SrH2 under hydrostatic conditions was measured, and the discovery of the novel SrH4 hydride.