Near-room-temperature superconductivity in hydrogen sulfide

2016

Sci Rep

The comparison study of high pressure superconducting state of recently synthesized H3S and PH3 compounds are conducted within the framework of the strong-coupling theory. By generalization of the standard Eliashberg equations to include the lowest-order vertex correction, we have investigated the influence of the nonadiabatic effects on the Coulomb pseudopotential, electron effective mass, energy gap function and on the 2Δ(0)/TC ratio. We found that, for a fixed value of critical temperature (178 K for H3S and 81 K for PH3), the nonadiabatic corrections reduce the Coulomb pseudopotential for H3S from 0.204 to 0.185 and for PH3 from 0.088 to 0.083, however, the electron effective mass and ratio 2Δ(0)/TC remain unaffected. Independently of the assumed method of analysis, the thermodynamic parameters of superconducting H3S and PH3 strongly deviate from the prediction of BCS theory due to the strong-coupling and retardation effects.

Section: Theoretical Model and Computational Methodsmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 86%

Quantitative analysis of nonadiabatic effects in dense H3S and PH3 superconductors

2016

Sci Rep

“…These materials were expected retain the superconducting properties of pure hydrogen but metallize at pressures significantly lower and reachable by current diamond anvil cell compression technique owing to the chemical pre-compression 5 , 16 . There is an essential hope that these materials can conduct electrical current at room-temperature without loss of energy 18 – 21 . Based on this idea, a lot of extensive theoretical studies have been carried out 22 – 26 .…”

Section: Introductionmentioning

confidence: 99%

Unusual sulfur isotope effect and extremely high critical temperature in H3S superconductor

Szczȩśniak

2018

Sci Rep

Recent experiments have set a new record for the transition temperature at which a material (hydrogen sulfide, H3S) becomes superconducting. Moreover, a pronounced isotope shift of TC in D3S is evidence of an existence of phonon-mediated pairing mechanism of superconductivity that is consistent with the well established Bardeen-Cooper-Schrieffer scenario. Herein, we reported a theoretical studies of the influence of the substitution of 32S atoms by the heavier isotopes 33S, 34S and 36S on the electronic properties, lattice dynamics and superconducting critical temperature of H3S. There are two equally fundamental results presented in this paper. The first one is an anomalous sulfur-derived superconducting isotope effect, which, if observed experimentally, will be subsequent argument that proves to the classical electron-phonon interaction. The second one is fact that critical temperature rise to extremely high value of 242 K for H336S at 155 GPa. This result brings us closer to the room temperature superconductivity.

“…The latest measurements of T c exceeding 200 K in H 3 S, [24][25][26][27][28] 243 K in YH 6 [29] and 250-260 K in LaH 10 [30][31][32] have affirmed that dense hydrogen-rich compounds can be promising candidates for room-temperature superconductors. [33] A very recent experimental study has reported superconductivity in carbonaceous sulfur hydride system with the highest T c of 288 K at 267 GPa proving roomtemperature superconductivity. [34] Even though many hydrides having high T c are widely classified as conventional superconductors whose pairing is mediated by H-derived high-frequency optical phonon modes, [35,36] the analysis of experimental upper critical field data, performed by Talantsev, [37,38] showed that H 3 S and LaH 10 are unconventional superconductors which lie in common unconventional superconductors trend band of the Uemura plot [39] including heavy fermions, fullerenes, pnictides, and cuprates.…”

Section: Introductionmentioning

confidence: 99%

“…The latest measurements of

T_{c}

exceeding 200 K in H 3 S, [ 24–28 ] 243 K in YH 6 [ 29 ] and 250–260 K in LaH 10 [ 30–32 ] have affirmed that dense hydrogen‐rich compounds can be promising candidates for room‐temperature superconductors. [ 33 ] A very recent experimental study has reported superconductivity in carbonaceous sulfur hydride system with the highest

T_{c}

of 288 K at 267 GPa proving room‐temperature superconductivity. [ 34 ]…”

Section: Introductionmentioning

confidence: 99%

Evidence of Phonon‐Mediated Superconductivity in LaH₁₀ at High Pressure

Wang

et al. 2020

Annalen der Physik

Motivated by the recent experimental discovery of the high‐critical‐temperature superconductor LaH10 (250–260 K at high pressures 170–190 GPa), the influence of H isotope substitution on the phonon spectra, electron–phonon interactions, and thermodynamic properties of superconducting LaH10−xDx (x=0,2,5,8,10) at 250 GPa are studied. On the basis of first‐principles calculations, it is found that all investigated systems are dynamically stable in a clathrate structure with space group Fm3¯m and exhibit high superconducting critical temperatures Tc ranging from 169 to 234 K. The dominant role of hydrogen in enhancing Tc is examined by numerically solving the Eliashberg equations. The estimated critical temperature, superconducting energy gap, specific heat, and thermodynamic critical field demonstrate that the underlying mechanism of superconductivity in lanthanum hydride is conventional electron–phonon coupling, which manifests itself in terms of isotope effect.