The electron-phonon coupling constant and the Debye temperature in polyhydrides of thorium, hexadeuteride of yttrium, and metallic hydrogen phase III

Abstract

Milestone experimental discovery of superconductivity above 200 K in highly-compressed sulphur hydride by Drozdov (Nature 525, 73 (2015)) sparked experimental and theoretical investigations of metallic hydrides. Since then, a dozen of superconducting binary and ternary polyhydrides have been discovered. For instance, there are three superconducting polyhydrides of thorium: Th4H15, ThH9, and ThH10 and four polyhydrides of yttrium: YH4, YH6, YH7, YH9. In addition to binary and ternary hydrogen-based metallic compounds, recently Eremets (arXiv:2109.11104) reported on the metallization of hydrogen, which exhibits a phase transition into metallic hydrogen phase III at P>330 GPa and T<200 K. Here we analyzed temperature-dependent resistance, R(T), in polyhydrides of thorium, hexadeuteride of yttrium and in hydrogen phase III and deduced the Debye temperature, $T$${}_{\theta }$, and the electron-phonon coupling constant, ${\lambda }_{e-ph}$, for these conductors. We found that Th4H15 phase exhibits ${\lambda }_{e-ph}$ = 0.82-0.99 which is in a very good agreement with experimental value of ${\lambda }_{e-ph}$ = 0.84 deduced from heat capacity measurements (Miller, Phys. Rev. B 14, 2795 (1976)). For P63/mmc-ThH9 phase (P = 170 GPa) we deduced ${\lambda }_{e-ph}$(170 GPa) = 1.46, which is in a reasonable agreement with ${\lambda }_{e-ph}$ reported by Semenok (Materials Today 33, 36 (2020)). Deduced ${\lambda }_{e-ph}$(170 GPa) = 1.70 for Fm-3m-ThH10 is in remarkable agreement with first-principles calculated ${\lambda }_{e-ph}$(174 GPa)=1.75 (Semenok, Materials Today 33, 36 (2020)). Deduced ${\lambda }_{e-ph}$(172 GPa) = 1.90 for Im-3m-YD6 is also in excellent agreement with first-principles calculated ${\lambda }_{e-ph}$(165 GPa)=1.80 (Troyan, Advanced Materials 33, 2006832 (2021)). And finally, we deduced $T$${}_{\theta }$(402 GPa) = 727 K for hydrogen phase III which implies that ${\lambda }_{e-ph}$(402 GPa)<1.7 in this metal.

arXiv comment30 pages, 12 figures

References in corpus (39)

• Conventional superconductivity at 203 K at high pressures
• Superconductivity at 250 K in lanthanum hydride under high pressures
• Evidence for superconductivity above 260 K in lanthanum superhydride at megabar pressures
• Crystal Structure of 200 K-Superconducting Phase of Sulfur Hydride System
• A Perspective on Conventional High-Temperature Superconductors at High Pressure: Methods and Materials
• Hydrogen sulphide at high pressure: a strongly-anharmonic phonon-mediated superconductor
• Anomalous high-temperature superconductivity in YH${}_6$
• Quantum Crystal Structure in the 250 K Superconducting Lanthanum Hydride
• Superconductivity at 161 K in Thorium Hydride $Th{H}_{10}$: Synthesis and Properties
• Superconductivity at 253 K in lanthanum-yttrium ternary hydrides
• High-Temperature Superconductivity in Cerium Superhydrides
• Superconducting hydrides under pressure
• Towards high-throughput superconductor discovery via machine learning
• Superconductivity in sodalite-like yttrium hydride clathrates
• Superconducting Praseodymium Superhydrides
• Actinium hydrides $Ac{H}_{10}$, $Ac{H}_{12}$, $Ac{H}_{16}$ as high-temperature conventional superconductors
• Universal self-field critical current for thin-film superconductors
• High-Pressure Synthesis of Barium Superhydrides: Pseudocubic BaH12
• Superconducting Phase-Diagram of H3S under High Magnetic Fields
• Quantitative analysis of nonadiabatic effects in dense H${}_3$S and PH${}_3$ superconductors
• Superconductivity up to 243 K in yttrium hydrides under high pressure
• Superconductivity above 100 K in PH3 at high pressures
• The vital role of hole-carriers for superconductivity in pressurized black phosphorus
• Superconductivity and Equation of State of Distorted fcc-Lanthanum above Megabar Pressures
• Anomalous critical fields in quantum critical superconductors
• London penetration depth and thermal fluctuations in the sulphur hydride 203 K superconductor
• Superconductivity of platinum hydride
• Energy gap closure of crystalline molecular hydrogen with pressure
• Pressure-induced Superconductivity in Tin Sulfide
• From LaH10 to room-temperature superconductors
• Physical properties and electronic structure of Sr${}_2$Cr${}_3$As${}_2$O${}_2$ containing CrO${}_2$ and Cr${}_2$As${}_2$ square-planar lattices
• Enhanced $T_c$ and multiband superconductivity in the fully-gapped ReBe${}_{22}$ superconductor
• Resistive transition of hydrogen-rich superconductors
• The dominance of non-electron-phonon charge carrier interaction in highly-compressed superhydrides
• Quantifying the charge carrier interaction in metallic twisted graphene superlattices
• High-Tc superconductivity in clathrate calcium hydride CaH6
• High-temperature superconductors as ionic metals
• Classifying charge carrier interaction in highly-compressed elements and silane
• Metallization of hydrogen

Cited by in corpus (10)

• Effect of paramagnetic impurities on superconductivity in polyhydrides: $\text{s}$-wave order parameter in Nd-doped LaH${}_{10}$
• Record-high-Tc elemental superconductivity in scandium
• Quantifying nonadiabaticity in major families of superconductors
• Universal Fermi velocity in highly compressed hydride superconductors
• Characteristic length for pinning force density in $Nb{}_{3}Sn$
• A-15 type superconducting hydride $L{a}_4{H}_{23}$: Nanograined structure with low strain, strong electron-phonon interaction, and moderate level of nonadiabaticity
• $d$-wave superconductivity as a model for diborides apart MgB${}_2$
• Method to extracting the penetration field in superconductors from DC magnetization data
• Fermi-liquid nonadiabatic highly-compressed cesium iodide superconductor
• Einstein and Debye temperatures, electron-phonon coupling constant and a probable mechanism for ambient-pressure room-temperature superconductivity in intercalated graphite