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Computational study of the potential room-temperature superconductor carbonaceous sulfur hydrideAlmansouri, Mahmoud 16 March 2022 (has links)
Research in superconductivity is heading towards overcoming the limitations imposed by extreme conditions, and promising candidates in this pursuit are superconductors made from hydrides. Carbonaceous Sulfur Hydride (CSH) was reported in Nature 586, 373-377 (2020) as a room-temperature superconductor in the pressure range of 140-267 GPa; however, there is controversy in the literature regarding these results. Here, we use density functional theory to confirm the hypothesis of Nature 596, E9-E10 (2021) that a metallic path is the reason for the sharp drop in resistance interpreted in Nature 586, 373-377 (2020) as indicative of a weak type 2 superconductor. We find that the metallic behavior of CSH is dominated by sulfur p-orbitals, and not by metallization of hydrogen. If CSH would be a superconductor, the predicted Ginzburg Landau parameter would be 1356.9, reflecting an unusually strong type 2 superconductor and thus contradicting the interpretation of Nature 586, 373-377 (2020). The fact that we find no metallic states below 220 GPa casts doubts on the onset of superconductivity at 140 GPa reported in Nature 586, 373-377 (2020). Additionally, the small fraction of active hydrogen density of states at the Fermi level shows that CSH is not a high-temperature superconductor.
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