Superconductivity Breakthrough: Stepping Stones to “Goldilocks” Superconductors

Cerium Superhydride High-Temperature Superconductor

Structure of cerium superhydride CeH10 synthesized by the researchers and shown to be a high-temperature superconductor. Credit: Pavel Odinev/Skoltech

New cerium superhydrides become stepping stones to “Goldilocks” superconductors.

Researchers from Skoltech and their colleagues from China have experimentally shown superconductivity in cerium superhydrides CeH9 and CeH10, pointing the way to lower-pressure and potentially room-temperature superconductors. The paper was published in the journal Physical Review Letters.

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 (we’re talking 135 K, or minus 138 degrees discovered earlier in 2019, and in the newly synthesized CeH10.

“Cerium hydrides are remarkable compounds. 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,” the authors write.

“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,” 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,” Dmitrii Semenok adds.

Credit: “High-Temperature Superconducting Phases in Cerium Superhydride with a Tc up to 115 K below a Pressure of 1 Megabar” by Wuhao Chen, Dmitrii V. Semenok, Xiaoli Huang, Haiyun Shu, Xin Li, Defang Duan, Tian Cui and Artem R. Oganov, 9 September 2021, Physical Review Letters.

DOI: 10.1103/PhysRevLett.127.117001

Other organizations involved in this research include Jilin University, Ningbo University, and the Center for High Pressure Science and Technology Advanced Research.