Clathrate Superhydrides Under High Pressure: A Class of Extraordinarily Hot Conventional Superconductors

Room-T superconductivity has been a century long-held dream of mankind and a focus of intensive research. In an effort to search for Room-T superconductors, we proposed the first-ever sodalite-like clathrate superhydride CaH₆ ¹ suffering at extreme pressures that shows a potential of high superconductivity and is not captured at ambient pressure.
We recently found a general phenomenon on the common formation of clathrate structures at high pressure in rare earth (RE) superhydrides having three stoichiometries of REH₆, REH₉, and REH₁₀, some of which exhibit high-T superconductivity². Subsequent experiments synthesized the predicted clathrate YH₆, YH₉, and LaH₁₀ with the measured T_c values at 224, 243, and 260 K, respectively, setting up T_c records among known superconductors. These discoveries open up the door of achieving Room-T superconductors.
In the talk, I will give an overview on the current status of research progress on superconductive hydrides, and then discuss the design principle for achieving Room-T superhydrides. As an example, our recent prediction on clathrate superhydride in Li-Mg-H ternary system³ with a predicted T_c at ~400 K will be discussed.
1Wang, et al., PNAS 109, 6463 (2012)
2Peng, et al., PRL 119, 107001 (2017)
3Sun, et al., PRL 123, 097001 (2019)