Superconducting $I$$\overline{4}$3$m$ CSH${}_7$ model applied to resistive transition temperature data for compressed C-S-H at high pressure

Abstract

This article updates version 1 by restricting consideration to only the resistive data and excluding the questioned 287.7-K datum reported for carbonaceous sulfur hydride in Snider et al., Nature $\text{585}$, 373 (2020). The superconducting transitions are considered in terms of the theoretically-discovered compressed $I$$\overline{\text{4}}$3$m$ CSH${}_7$ structure of Sun et al., Phys. Rev. B $\text{101}$, 174102 (2020), which comprises a sublattice similar to $Im$$\overline{\text{3}}$$m$ H${}_3$S with CH${}_4$ intercalates. Positing an electronic genesis of the superconductivity, a model is presented in analogy with earlier work on superconductivity in $Im$$\overline{\text{3}}$$m$ H${}_3$S, in which pairing is induced via purely electronic Coulomb interactions across the mean distance $\zeta$ between the S and H${}_4$ tetrahedra enclosing C. Theoretical superconducting transition temperatures for $I$$\overline{\text{4}}$3$m$ CSH${}_7$ are derived as $T$${}_{\text{C0}}$ = (2/3)${}^{1/2}$ ${\sigma }^{1/2}$ $\beta$/$a$$\zeta$, where $\beta$ = 1247.4 $\mathring{\mathrm{A}}$${}^2$K is a universal constant, $\sigma$ is the participating charge fraction, and $a$ is the lattice parameter. Analysis suggests persistent bulk superconductivity with a pressure-dependent $\sigma$, increasing from $\sigma$ = 3.5, determined previously for $Im$$\overline{3}$$m$ H${}_3$S, to $\sigma$ = 7.5 at high pressure owing to additionally participating C-H bond electrons. With $a$ and $\zeta$ determined by theoretical structure, calculations of $T$${}_{\text{C0}}$ at the highest pressures, 258 and 271 GPa, are in agreement with resistive transitions to within an overall uncertainty of $\pm$ 3.5 K.

10 pages, 5 figures, 1 table. This article updates version 1 by restricting consideration to only the resistive data and excluding the questioned 287.7-K datum reported for carbonaceous sulfur hydride in Snider et al., Nature $\text{585}$. 373 (2020). (the figures, table, and some of the calculated parameters are adjusted accordingly)

References in corpus (12)

• Hole-Doped Room-Temperature Superconductivity in H${}_3$S${}_{1-x}$Z${}_x$ (Z=C, Si)
• Anomalous behavior in high-pressure carbonaceous sulfur hydride
• Theory of High-Tc Superconductivity: Accurate Predictions of Tc
• X-ray Diffraction and Equation of State of the C-S-H Room-Temperature Superconductor
• The electron-phonon coupling constant, the Fermi temperature and unconventional superconductivity in the carbonaceous sulfur hydride 190 K superconductor
• Synthesis and structure of carbon doped H3S compounds at high pressure
• On the isotope effect in compressed superconducting H${}_{\text{3}}$S and D${}_{\text{3}}$S
• High-$T$${}_{\text{C}}$ Superconductivity in Hydrogen Clathrates Mediated by Coulomb Interactions between Hydrogen and Central-Atom Electrons
• Carbon-Doped Sulfur Hydrides as Room-Temperature Superconductors at 270 GPa
• High-$T_{\text{C}}$ superconductivity in Cs${}_3$C${}_{60}$ compounds governed by local Cs-C${}_{60}$ Coulomb interactions
• Superconductivity of CH4-intercalated H3S under high pressure
• High Pressure RTSC-Hydrides are Extreme Hard Type-II Superconductors

Cited by in corpus (3)

• Universal Fermi velocity in highly compressed hydride superconductors
• Electron-phonon coupling constant and BCS ratios in (La,Nd)-H superhydride
• Crystal Chemistry at High Pressure