The experimental discovery of antimony polyhydride superconductor with Tc up to 116K

Researchers at Institute of Physics Chinese Academy of Sciences(IOPCAS) report the discovery of superconductivity (SC) with T_c ~116 K in new antinomy polyhydride SbH₄, which has the second highest T_c among the covalent bonding dominated polyhydrides. The paper was published in National Science Review 11, nwad241 (2024).

The experimental discovery of SC with T_c~203 K in SH₃ has sparked great enthusiasm to exploring new high-temperature superconducting pollyhydride. Recently, pollyhydride superconductor exploration mainly focuses on the elements with low electronegativity, such as rare-earth and alkaline-earth metals, and near room temperature SC with T_c >200 K has been found in the ion bonding dominated pollyhydrides of lanthanum, yttrium, and calcium, respectively. However, there have been few experimental reports on pollyhydride superconductors with covalent bonding.

In the main groups from IIIA to VIIA, most of the non-metallic elements have high electronegativity and usually form covalent bonding with hydrogen. Therefore, the research team led by Prof. Changqing Jin from IOPCAS try to explore new pollyhydride superconductors with covalent bonding among the non-metallic elements. The diamond anvil cell combined with laser heating technique was used to synthesize the polyhydride samples under high pressure and high temperature conditions. In–situ high pressure transport measurements were performed to study the SC properties. Currently, they have successfully synthesized antimony polyhydride and found that the sample shows superconducting transition at 116 K under 184 GPa. It is proposed that the superconducting phase possibly arises from the P6₃/mmc-SbH₄. In the SbH₄ lattice, the shortest H-H length forming conducting path is 1.73 Å, which is significantly larger than the typical value of 1.0-1.2 Å in ion bonding dominated polyhydride superconductors. Their results suggest that hydrogen atoms with moderate distance could be metallized and realize superconductivity via the formation of metallic covalent bonding with the second element.

The study entitled “Superconductivity with T_c 116 K Discovered in Antimony Polyhydrides” was published in National Science Review 11, nwad241 (2024) at https://doi.org/10.1093/nsr/nwad241.

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Journal: National Science Review
DOI: 10.1093/nsr/nwad241