The 6th International Conference on Matter and Radiation at Extremes (ICMRE2023)

In the past decade, the discovery of SH₃[1], CaH₆[2], and LaH₁₀[3-4] with T_c exceeding 200 K ignited the enthusiasm for high-temperature superconductors under high pressure. No other recognized hydride with T_c higher than LaH₁₀ has been obtained experimentally, although almost all binary hydrides with various stoichiometries have been theoretically and experimentally investigated. At present, the research focus has thus shifted to the ternary system with a higher degree of freedom, which bring new opportunities for the search for a high-temperature superconductor under high pressure[5]. Although a larger number of theoretical studies have indicated that ternary hydrides may host excellent supercomputing properties, high-pressure experiments about ternary systems are still in their infancy. Recently, we successfully synthesized and characterized a series of ternary high-T_c polyhydrides[6-7] near megabar pressure with diamond anvil cell technique, such as (La,Ce)H₉ that provides clear experimental evidence of giant T_c enhancement. Our experimental results establish an important paradigm in search of new ternary high-T_c superhydrides via a suitable combination of metal elements.