Superconductivity in elemental yttrium and yttrium superhydride bulk and film at high pressures*

The quest for room temperature superconductivity has always been one of the most intense topics in condensed matter physics. It has reached its peak with the recent discovery of several superhydride compounds exhibiting superconductivity at vicinity of room temperature under megabars pressures, such as YH₉. While theoretical works are paving the way to realize new hydrides superconductors, their synthesis within the laboratory remains very challenging. Here we demonstrate a new approach to synthesize YH_x from an elemental yttrium film directly evaporated on the diamond anvil [1]. This method allows a more accurate control of the sample size and helps to reach an ideal stoichiometry in the synthesis. Our measurements show that electronic properties of elemental yttrium bulk and film are similar. Superconducting temperatures we measure in elemental yttrium under megabar pressures together with a re-analyse of previous x-ray data provide evidence of the predicted Fddd phase above 100 GPa. Furthermore, we will show that it is possible to synthetize an yttrium superhydride superconductor film.

[1] J. Buhot et al. Phys. Rev. B 102, 104508 (2020)