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 (42)

• Conventional superconductivity at 203 K at high pressures
• Superconductivity at 250 K in lanthanum hydride under high pressures
• Very High Field Two-Band Superconductivity in LaFeAsO_0.89F_0.11
• Nearly Isotropic superconductivity in (Ba,K)Fe2As2
• Anomalous high-temperature superconductivity in YH${}_6$
• Quantum Crystal Structure in the 250 K Superconducting Lanthanum Hydride
• Quantum Hydrogen-Bond Symmetrization and High-Temperature Superconductivity in Hydrogen Sulfide
• Universal $T$-linear resistivity and Planckian limit in overdoped cuprates
• Superconductivity at 253 K in lanthanum-yttrium ternary hydrides
• High-Temperature Superconductivity in Cerium Superhydrides
• Superconducting hydrides under pressure
• Effective Demagnetization Factors of Diamagnetic Samples of Various Shapes
• 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
• Breakdown of Migdal-Eliashberg theory; a determinant quantum Monte Carlo study
• The Strange Metal State of the Electron-Doped Cuprates
• Pauli-limiting effects in the upper critical fields of a clean LiFeAs single crystal
• Disorder and Quantum Fluctuations in Superconducting Films in Strong Magnetic Fields
• High-temperature superconductivity on the verge of a structural instability in lanthanum superhydride
• Trapped magnetic flux in hydrogen-rich high-temperature superconductors
• Room Temperature Superconductivity: the Roles of Theory and Materials Design
• Origin of High-Temperature Superconductivity in Compressed LaH${}_{10}$
• Effect of paramagnetic impurities on superconductivity in polyhydrides: $\text{s}$-wave order parameter in Nd-doped LaH${}_{10}$
• Interaction corrections to the Hall coefficient at intermediate temperatures
• High T_c superconductivity due to coexisting wide and narrow bands: A fluctuation exchange study on the Hubbard ladder as a test case
• Multiband Nature of the Room-Temperature Superconductivity in Compressed LaH${}_{10}$
• Magnetization asymmetry of type-II superconductors in high magnetic fields
• Linear magnetoresistance in the charge density wave state of quasi-two-dimensional rare-earth tritellurides
• Speed of sound from fundamental physical constants
• Meissner effect in nonstandard superconductors
• Non-Fermi-Liquid Behavior of Superconducting SnH${}_4$
• High-$T_c$ superconducting hydrides formed by LaH${}_{24}$ and YH${}_{24}$ cage structures as basic blocks
• Large negative magnetoresistance and pseudogap phase in superconducting A15-type La${}_4$H${}_{23}$
• Quantum meets classical phase transition: Low-temperature anomaly in disordered superconductors near $B_{c2}$
• Resistive transition of hydrogen-rich superconductors
• Electrons with Planckian scattering obey standard orbital motion in a magnetic field
• Electron-phonon coupling and superconductivity in an alkaline earth hydride CaH${}_6$ at high pressures
• Large linear magnetoresistance and magnetothermopower in layered SrZnSb${}_2$
• Synthesis and structure of carbon doped H3S compounds at high pressure
• Electron-phonon coupling constant and BCS ratios in (La,Nd)-H superhydride
• Antiadiabatic Phonons and Superconductivity in Eliashberg-McMillan Theory

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