M. N. Miheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, 18, S. Kovalevskoy St., Ekaterinburg 620108, Russia and NANOTECH Centre, Ural Federal University, 19 Mira St., Ekaterinburg 620002, Russia
Evgeny F. Talantsev. Universal Fermi velocity in highly compressed hydride superconductors[J]. Matter and Radiation at Extremes, 2022, 7(5): 058403
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The Fermi velocity vF is one of the primary characteristics of any conductor, including any superconductor. For conductors at ambient pressure, several experimental techniques have been developed to measure vF, and, for instance, Zhou et al. [Nature 423, 398 (2003)] reported that high-Tc cuprates exhibited a universal nodal Fermi velocity m/s. However, there have been no measurements of vF in highly compressed near-room-temperature superconductors (NRTS), owing to experimental challenges. Here, to answer the question of the existence of a universal Fermi velocity in NRTS materials, we analyze the full inventory of data on the ground-state upper critical field Bc2(0) for these materials and find that this class of superconductors exhibits a universal Fermi velocity m/s, where Δ(0) is the ground-state amplitude of the energy gap. The ratio varies within a narrow range , and so vF,univ in NRTS materials lies in the range 2.5 × 105 m/s ≤ vF,univ ≤ 3.8 × 105 m/s, which is similar to the range of values found for the high-Tc cuprate counterparts of these materials.