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Evidence for superconductivity above 260 K in lanthanum superhydride at megabar pressures

2018/08/23 by Maddury Somayazulu, Muhtar Ahart, Ajay K. Mishra +6 · 1 voice · 1,453 citations
Earth and Planetary Sciences · Physics and Astronomy · #Advanced Chemical Physics Studies #Condensed matter physics #Diffraction #Electrical resistivity and conductivity #High-pressure geophysics and materials #Hydrogen #Lanthanum #Materials science #Nuclear physics #Optics #Physics #Physics of Superconductivity and Magnetism #Superconductivity #cond-mat.mtrl-sci

paper · pdf · doi:10.1103/physrevlett.122.027001

published in Physical Review Letters 122(2), 027001 (American Physical Society) · 20 pages, 4 figures and Supplementary Materials , added some references, edited and corrected several typos, no change in results

arxiv created 2018/08/29 · openalex publication_date 2019/01/14 · arxiv updated 2019/01/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

Recent predictions and experimental observations of high Tc superconductivity in hydrogen-rich materials at very high pressures are driving the search for superconductivity in the vicinity of room temperature. We have developed a novel preparation technique that is optimally suited for megabar pressure syntheses of superhydrides using pulsed laser heating while maintaining the integrity of sample-probe contacts for electrical transport measurements to 200 GPa. We detail the synthesis and characterization, including four-probe electrical transport measurements, of lanthanum superhydride samples that display a significant drop in resistivity on cooling beginning around 260 K and pressures of 190 GPa. Additional measurements on two additional samples synthesized the same way show resistance drops beginning as high as 280 K at these pressures. The loss of resistance at these high temperatures is not observed in control experiments on pure La as well as in partially transformed samples at these pressures, and x-ray diffraction as a function of temperature on the superhydride reveal no structural changes on cooling. We infer that the resistance drop is a signature of the predicted room-temperature superconductivity in LaH10, in good agreement with density functional structure search and BCS theory calculations.

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