The road to superconductivity, an extremely attractive physical property of some materials that do not lose energy to heat because they have zero resistance, lies through tough terrain. It requires either extremely low temperatures (135 K, or minus 138 degrees Celsius, at the warmest) or extremely high pressure (in 2019, LaH10 was found to become superconducting at -23 C and 1.7 million atmospheres, and in 2020 a S-C-H compound was found to superconduct at +15 C and 2.7 million atmospheres).
“Cerium hydrides are remarkable compounds,” say the researchers, “stable and displaying high-temperature superconductivity at lower pressures than any other superhydrides (about 0.8 million atmospheres), they serve as an ideal starting point to further study the mechanism of superconductivity in these fascinating compounds, and design other superconductors, stable at even lower pressures.”
“Earlier we established a remarkably close relationship between the periodic table and superconductivity of hydrides — and we believe it should apply not just to hydrides! Take La and Ce — they are neighbors in the periodic table and indeed both form high-temperature superconductors. However, there are differences: LaH10 superconducts at higher temperatures, while CeH10 is stable at lower pressures,” says researcher Artem R. Oganov says.
The authors point out that now binary hydrides are mostly explored. “Now we need to carefully think how to combine the elements to achieve higher-temperature superconductivity at lower pressures in ternary hydrides. We know which elements lead to higher-temperature superconductivity and begin to learn which lead to stability at lower pressures. These are the main notes, but it takes imagination to combine them in a melody,” says researcher Dmitrii Semenok.