Missing theoretical evidence for conventional room-temperature superconductivity in low-enthalpy structures of carbonaceous sulfur hydrides

Gubler, Moritz; Flores‐Livas, José A.; Kozhevnikov, Anton; Goedecker, Stefan

doi:10.1103/physrevmaterials.6.014801

Cited by 25 publications

(14 citation statements)

References 27 publications

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“…63,66,70 One might think that the point here is the formation of true ternary and quaternary polyhydrides. But a detailed theoretical analysis shows 66,71 that this can hardly lead to high-TC superconductivity in the framework of the BCS theory. Experimental results 63 also do not allow us to draw unambiguous conclusions.…”

Section: Discussionmentioning

confidence: 99%

Effect of paramagnetic impurities on superconductivity in polyhydrides: s-wave order parameter in Nd-doped LaH10

Semenok

Troyan

Sadakov

et al. 2022

Preprint

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Polyhydrides are a novel class of superconducting materials with extremely high critical parameters, which is very promising for applications. On the other hand, complete experimental study of the magnetic phase diagram for the best so far known superconductor, lanthanum decahydride LaH10, encounters a serious complication because of the large upper critical magnetic field HC2(0), exceeding 120–160 T. Partial replacement of La atoms by magnetic Nd atoms results in a decrease of the upper critical field, which makes it attainable for existing pulse magnets. We found that addition of neodymium leads to significant suppression of superconductivity in LaH10: each atomic % of Nd causes decrease in TC by 10–11 K. Using strong pulsed magnetic fields up to 68 T, we constructed the magnetic phase diagram of the ternary (La,Nd)H10 superhydride, which appears to be surprisingly linear with HC2 ∝ |T – TC|. The pronounced suppression of superconductivity in LaH10 by magnetic Nd atoms and the robustness of TC with respect to nonmagnetic impurities (e.g., Y, Al, C) under Anderson’s theorem indicate the isotropic (s‑wave) character of conventional electron-phonon pairing in the synthesized superhydrides.

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Section: Discussionmentioning

confidence: 99%

Effect of paramagnetic impurities on superconductivity in polyhydrides: s-wave order parameter in Nd-doped LaH10

Semenok

Troyan

Sadakov

et al. 2022

Preprint

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“…More recently, room-temperature superconductivity was announced first at 288 K under a pressure of 276 GPa [24] and then at 294 K at 21 GPa [25] in the same sulfur-carbonhydrogen system. However, these contradictory measurements with no access to the raw data have found serious criticism [5,[26][27][28][29]. After more than a year, room-temperature superconductivity in the sulfur-carbon-hydrogen system was neither confirmed experimentally nor supported by theoretical calculations.…”

Section: Introductionmentioning

confidence: 99%

High-Temperature Superconductivity in Hydrides: Experimental Evidence and Details

Eremets

Minkov

Дроздов

et al. 2022

J Supercond Nov Magn

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Since the discovery of superconductivity at ~ 200 K in H3S [1], similar or higher transition temperatures, Tcs, have been reported for various hydrogen-rich compounds under ultra-high pressures [2]. Superconductivity was experimentally proved by different methods, including electrical resistance, magnetic susceptibility, optical infrared, and nuclear resonant scattering measurements. The crystal structures of superconducting phases were determined by X-ray diffraction. Numerous electrical transport measurements demonstrate the typical behavior of a conventional phonon-mediated superconductor: zero resistance below Tc, shift of Tc to lower temperatures under external magnetic fields, and pronounced isotope effect. Remarkably, the results are in good agreement with the theoretical predictions, which describe superconductivity in hydrides within the framework of the conventional BCS theory. However, despite this acknowledgement, experimental evidences for the superconducting state in these compounds have recently been treated with criticism [3–7], which apparently stems from misunderstanding and misinterpretation of complicated experiments performed under very high pressures. Here, we describe in greater detail the experiments revealing high-temperature superconductivity in hydrides under high pressures. We show that the arguments against superconductivity [3–7] can be either refuted or explained. The experiments on the high-temperature superconductivity in hydrides clearly contradict the theory of hole superconductivity [8] and eliminate it [3].

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“…Among these hydrogen-based superconductors, clathrate hydrides are one type that exists widely, including the well-known CaH 6 with H 24 cage [15], YH 9 with H 29 cage [16], and LaH 10 with H 32 cage [11,12]. The clathrate hexahydrides Im-3m-XH 6 (X = Mg, Ca, Sc, Y, La, Tm, Yb, and Lu) are prevalent in alkaline earth and rare earth metal hydride [12,15,[17][18][19][20], in which, the metal atoms form a body centered cubic (bcc) lattice, and hydrogen atoms occupy all the tetrahedral voids of the bcc lattice, forming a H 24 cage.…”

Section: Introductionmentioning

confidence: 99%

“…However, the stoichiometry and crystal structure of this compound have not yet been determined. This experiment is still subject to many controversies [16,27,28]. Although the T c s of Li 2 MgH 16 and C-S-H compounds can reach room temperature, the extreme pressure above 250 GPa also makes them difficult in practical application.…”

Section: Introductionmentioning

confidence: 99%

Room-Temperature Superconductivity in Yb/Lu Substituted Clathrate Hexahydrides under Moderate Pressure

Song

Zhang

et al. 2022

Research

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Room temperature superconductivity is a dream that mankind has been chasing for a century. In recent years, the synthesis of H3S, LaH10, and C-S-H compounds under high pressures has gradually made that dream become a reality. But the extreme high pressure required for stabilization of hydrogen-based superconductors limit their applications. So, the next challenge is to achieve room-temperature superconductivity at significantly low pressures, even ambient pressure. In this work, we design a series of high temperature superconductors that can be stable at moderate pressures by incorporating heavy rare earth elements Yb/Lu into sodalite-like clathrate hexahydrides. In particular, the critical temperatures (Tc) of Y3LuH24, YLuH12, and YLu3H24 can reach 283 K at 120 GPa, 275 K at 140 GPa, and 288 K at 110 GPa, respectively. Their critical temperatures are close to or have reached room temperature, and minimum stable pressures are significantly lower than that of reported room temperature superconductors. Our work provides an effective method for the rational design of low-pressure stabilized hydrogen-based superconductors with room-temperature superconductivity simultaneously and will stimulate further experimental exploration.

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Missing theoretical evidence for conventional room-temperature superconductivity in low-enthalpy structures of carbonaceous sulfur hydrides

Cited by 25 publications

References 27 publications

Effect of paramagnetic impurities on superconductivity in polyhydrides: s-wave order parameter in Nd-doped LaH10

Effect of paramagnetic impurities on superconductivity in polyhydrides: s-wave order parameter in Nd-doped LaH10

High-Temperature Superconductivity in Hydrides: Experimental Evidence and Details

Room-Temperature Superconductivity in Yb/Lu Substituted Clathrate Hexahydrides under Moderate Pressure

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