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Pressure and high-T(c) superconductivity in sulfur hydrides
The paper discusses fundamentals of record-T(C) superconductivity discovered under high pressure in sulfur hydride. The rapid increase of T(C) with pressure in the vicinity of P(cr) ≈ 123GPa is interpreted as the fingerprint of a first-order structural transition. Based on the cubic symmetry of the...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4863257/ https://www.ncbi.nlm.nih.gov/pubmed/27167334 http://dx.doi.org/10.1038/srep25608 |
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author | Gor’kov, Lev P. Kresin, Vladimir Z. |
author_facet | Gor’kov, Lev P. Kresin, Vladimir Z. |
author_sort | Gor’kov, Lev P. |
collection | PubMed |
description | The paper discusses fundamentals of record-T(C) superconductivity discovered under high pressure in sulfur hydride. The rapid increase of T(C) with pressure in the vicinity of P(cr) ≈ 123GPa is interpreted as the fingerprint of a first-order structural transition. Based on the cubic symmetry of the high-T(C) phase, it is argued that the lower-T(C) phase has a different periodicity, possibly related to an instability with a commensurate structural vector. In addition to the acoustic branches, the phonon spectrum of H(3)S contains hydrogen modes with much higher frequencies. Because of the complex spectrum, usual methods of calculating T(C) are here inapplicable. A modified approach is formulated and shown to provide realistic values for T(C) and to determine the relative contributions of optical and acoustic branches. The isotope effect (change of T(C) upon Deuterium for Hydrogen substitution) originates from high frequency phonons and differs in the two phases. The decrease of T(C) following its maximum in the high-T(C) phase is a sign of intermixing with pairing at hole-like pockets which arise in the energy spectrum of the cubic phase at the structural transition. On-pockets pairing leads to the appearance of a second gap and is remarkable for its non-adiabatic regime: hydrogen mode frequencies are comparable to the Fermi energy. |
format | Online Article Text |
id | pubmed-4863257 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Nature Publishing Group |
record_format | MEDLINE/PubMed |
spelling | pubmed-48632572016-05-23 Pressure and high-T(c) superconductivity in sulfur hydrides Gor’kov, Lev P. Kresin, Vladimir Z. Sci Rep Article The paper discusses fundamentals of record-T(C) superconductivity discovered under high pressure in sulfur hydride. The rapid increase of T(C) with pressure in the vicinity of P(cr) ≈ 123GPa is interpreted as the fingerprint of a first-order structural transition. Based on the cubic symmetry of the high-T(C) phase, it is argued that the lower-T(C) phase has a different periodicity, possibly related to an instability with a commensurate structural vector. In addition to the acoustic branches, the phonon spectrum of H(3)S contains hydrogen modes with much higher frequencies. Because of the complex spectrum, usual methods of calculating T(C) are here inapplicable. A modified approach is formulated and shown to provide realistic values for T(C) and to determine the relative contributions of optical and acoustic branches. The isotope effect (change of T(C) upon Deuterium for Hydrogen substitution) originates from high frequency phonons and differs in the two phases. The decrease of T(C) following its maximum in the high-T(C) phase is a sign of intermixing with pairing at hole-like pockets which arise in the energy spectrum of the cubic phase at the structural transition. On-pockets pairing leads to the appearance of a second gap and is remarkable for its non-adiabatic regime: hydrogen mode frequencies are comparable to the Fermi energy. Nature Publishing Group 2016-05-11 /pmc/articles/PMC4863257/ /pubmed/27167334 http://dx.doi.org/10.1038/srep25608 Text en Copyright © 2016, Macmillan Publishers Limited http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
spellingShingle | Article Gor’kov, Lev P. Kresin, Vladimir Z. Pressure and high-T(c) superconductivity in sulfur hydrides |
title | Pressure and high-T(c) superconductivity in sulfur hydrides |
title_full | Pressure and high-T(c) superconductivity in sulfur hydrides |
title_fullStr | Pressure and high-T(c) superconductivity in sulfur hydrides |
title_full_unstemmed | Pressure and high-T(c) superconductivity in sulfur hydrides |
title_short | Pressure and high-T(c) superconductivity in sulfur hydrides |
title_sort | pressure and high-t(c) superconductivity in sulfur hydrides |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4863257/ https://www.ncbi.nlm.nih.gov/pubmed/27167334 http://dx.doi.org/10.1038/srep25608 |
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