Progress, problems and prospects of room-temperature superconductivity

Abstract

Discovery of superconductivity at megabar (MB) pressures in hydrogen sulfide H3S, then in metal polyhydrides, starting with binary, LaH10, etc., and ending with ternary ones, including (La, Y)H10, revolutionized the field of condensed matter physics. These discoveries strengthen hopes for solution of the century-old problem of creating materials that are superconducting at room temperature. In experiments performed over the past 5 years at MB pressures, in addition to the synthesis of hydrides itself, their physical properties were studied using optical, X-ray and Mossbauer spectroscopy, as well as galvanomagnetic measurement techniques. This paper presents the major results of galvanomagnetic studies, including measurements in high static (up to 21T) and pulsed (up to 70T) magnetic fields. Measurements of resistance drops to vanishingly small level at temperatures below the critical Tc value, a decrease in the critical temperature Tc with increasing magnetic field, as well as diamagnetic screening, indicate the superconducting state of the polyhydrides. The results of measurements of the isotope effect, together with the effect of magnetic impurities on Tc, indicate the electron-phonon mechanism of electron pairing. However, electron-electron correlations in polyhydrides are by no means small, both in the superconducting and normal states. It is possible that this is precisely what accounts for the unusual properties of polyhydrides that have not yet received a satisfactory explanation, such as a linear temperature dependence of the second critical field Hc2(T), a linear dependence of resistance R(T), and a linear magnetoresistance, very similar to that discovered by P. L. Kapitza in 1929.

References in corpus (15)

• Very High Field Two-Band Superconductivity in LaFeAsO_0.89F_0.11
• Nearly Isotropic superconductivity in (Ba,K)Fe2As2
• Superconducting hydrides under pressure
• Superconductivity in sodalite-like yttrium hydride clathrates
• Enhancement of the superconducting critical temperature realized in the La-Ce-H system at moderate pressures
• Efficient route to achieve superconductivity improvement via substitutional La-Ce alloy superhydride at high pressure
• Trapped magnetic flux in hydrogen-rich high-temperature superconductors
• Room Temperature Superconductivity: the Roles of Theory and Materials Design
• Effect of paramagnetic impurities on superconductivity in polyhydrides: $\text{s}$-wave order parameter in Nd-doped LaH${}_{10}$
• Linear magnetoresistance in the charge density wave state of quasi-two-dimensional rare-earth tritellurides
• Non-Fermi-Liquid Behavior of Superconducting SnH${}_4$
• Large negative magnetoresistance and pseudogap phase in superconducting A15-type La${}_4$H${}_{23}$
• Electrons with Planckian scattering obey standard orbital motion in a magnetic field
• Resistive transition of hydrogen-rich superconductors
• Electron-phonon coupling constant and BCS ratios in (La,Nd)-H superhydride

Cited by in corpus (4)

• A-15 type superconducting hydride $L{a}_4{H}_{23}$: Nanograined structure with low strain, strong electron-phonon interaction, and moderate level of nonadiabaticity
• On the trapped magnetic moment in type-II superconductors
• Upper limit for superconducting transition temperature in electron-phonon superconductors: very strong coupling
• Einstein and Debye temperatures, electron-phonon coupling constant and a probable mechanism for ambient-pressure room-temperature superconductivity in intercalated graphite