Synthesis and superconductivity in yttrium superhydrides under high pressure
Yingying Wang, Kui Wang, Yao Sun, Liang Ma, Yanchao Wang, Bo Zou, Guangtao Liu, Mi Zhou, Hongbo Wang
Abstract
Flourishing rare earth superhydrides are a class of recently discovered materials that exhibit near-room-temperature superconductivity at high pressures, ushering in a new era of superconductivity research at high pressures. Yttrium superhydrides drew the most attention among these superhydrides due to their abundance of stoichiometries and excellent superconductivities. Here, we carried out a comprehensive study of yttrium superhydrides in a wide pressure range of 140 GPa–300 GPa. We successfully synthesized a series of superhydrides with the compositions of YH 4 , YH 6 , YH 7 , and YH 9 , and reported superconducting transition temperatures of 82 K at 167 GPa, 218 K at 165 GPa, 29 K at 162 GPa, and 230 K at 300 GPa, respectively, as evidenced by sharp drops in resistance. The structure and superconductivity of YH 4 were taken as a representative example and were also examined using x-ray diffraction measurements and the superconductivity suppression under external magnetic fields, respectively. Clathrate YH 10 , a candidate for room-temperature superconductor, was not synthesized within the study pressure and temperature ranges of up to 300 GPa and 2000 K. The current study established a detailed foundation for future research into room-temperature superconductors in polynary yttrium-based superhydrides.