{"id":3993,"date":"2017-09-17T12:36:43","date_gmt":"2017-09-17T19:36:43","guid":{"rendered":"http:\/\/physikon.net\/?p=3993"},"modified":"2022-06-22T09:37:19","modified_gmt":"2022-06-22T16:37:19","slug":"compressed-h3s-inter-sublattice-coulomb-coupling-in-a-high-tc-superconductor","status":"publish","type":"post","link":"http:\/\/physikon.net\/?p=3993","title":{"rendered":"Compressed H3<\/sub>S: Inter-Sublattice Coulomb Coupling in a High-Tc<\/sub> Superconductor"},"content":{"rendered":"

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Compressed H3<\/sub>S: inter-sublattice Coulomb coupling in a high-T<\/em>C<\/sub> superconductor<\/strong>, D. R. Harshman and A. T. Fiory\u00a0[arXiv<\/a>]\n

Upon thermal annealing at or above room temperature (RT) and at high hydrostatic pressure P<\/em> ~ 155 GPa, sulfur trihydride H3<\/sub>S exhibits a measured maximum superconducting transition temperature T<\/em>\u00adC<\/sub> ~ 200 K.\u00a0 Various theoretical frameworks incorporating strong electron-phonon coupling and Coulomb repulsion have reproduced this record-level T<\/em>C<\/sub>.\u00a0 Of particular relevance is that experimentally observed H-D isotopic correlations among T<\/em>C<\/sub>, P<\/em>, and annealed order indicate an H-D isotope effect exponent \u03b1 limited to values \u2264 0.183, leaving open for consideration unconventional high-T<\/em>C<\/sub> superconductivity with electronic-based enhancements.\u00a0 The work presented herein examines Coulombic pairing arising from interactions between neighboring S and H species on separate interlaced sublattices constituting H3<\/sub>S in the Im3<\/span>m structure.\u00a0 The optimal value of the transition temperature is calculated from T<\/em>C0<\/sub> = k<\/em>B<\/sub>\u20131<\/sup>\u039be<\/em>2<\/sup>\/\u2113\u03b6, with \u039b= 0.007465 \u00c5, inter-sublattice S-H separation spacing \u03b6 = a<\/em>0<\/sub>\/\u221a<\/span>2<\/span>, interaction charge linear spacing \u2113 = a<\/em>0<\/sub> (3\/\u03c3)1\/2<\/sup>, average participating charge fraction \u03c3 = 3.43 \u00b1 0.10 estimated from calculated H-projected electron states, and lattice parameter a<\/em>0<\/sub> = 3.0823 \u00c5 at P<\/em> = 155 GPa. \u00a0The resulting value of T<\/em>C0<\/sub> = 198.5 \u00b1 3.0 K is in excellent agreement with transition temperatures determined from resistivity (196 – 200 K onsets, 190 – 197 K midpoints), susceptibility (200 K onset), and critical magnetic fields (203.5 K by extrapolation).\u00a0 Analysis of mid-infrared reflectivity data confirms the expected correlation between boson energy and \u03b6\u20131<\/sup>.\u00a0Suppression of T<\/em>C<\/sub> below T<\/em>C0<\/sub>, correlating with increasing residual resistance for <\u00a0RT annealing, is treated in terms of scattering-induced pair breaking.\u00a0Correspondences between H3<\/sub>S and layered high-T<\/em>C<\/sub> superconductor structures are also discussed, and a model considering Compton scattering of virtual photons of energies \u2264 e<\/em>2<\/sup>\/\u03b6 by inter-sublattice electrons is introduced, illustrating that \u039b \u221d \u019bC<\/sub>, where \u019bC<\/sub> is the reduced electron Compton wavelength.<\/p>\n\n\n\n\n\t\n\t
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Illustration of Im3<\/span>m unit cell of compressed H3<\/sub>S with color contrast distinguishing the two simple cubic sublattices; basis H3<\/sub>S is shown with S larger than H. Lattice parameter a<\/em>0<\/sub> is cube edge; inter-sublattice S-H distance ζ is one-half cube face diagonal.<\/p><\/td>\n<\/tr>\n

Variation of measured T<\/em>C<\/sub> of H3<\/sub>S with applied pressure P for \u2265 RT (room temperature) anneal, green circles with center dot, and < RT anneal, blue circles (from [1, 5, 6]). Gray symbols are various theoretical calculations denoted as (D) [2], (E) [4], (P) [8], (A) [10], (K) [11], (G) [13], (F) [14], (S) [16], (\u041a) [17], and (J) [18]; structure indicated where available. Red square symbol (H) corresponds to TC0<\/sub> from this work.<\/p><\/td>

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Dale R. Harshman and Anthony T. Fiory,\u00a0Journal of Physics: Condensed Matter\u00a0 29<\/strong>, 445702 (2017)<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":4015,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,8,28],"tags":[],"class_list":["post-3993","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-high-tc-superconductivity","category-high-tc-theory","category-transition-temperature"],"_links":{"self":[{"href":"http:\/\/physikon.net\/index.php?rest_route=\/wp\/v2\/posts\/3993","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/physikon.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/physikon.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/physikon.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/physikon.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3993"}],"version-history":[{"count":54,"href":"http:\/\/physikon.net\/index.php?rest_route=\/wp\/v2\/posts\/3993\/revisions"}],"predecessor-version":[{"id":7691,"href":"http:\/\/physikon.net\/index.php?rest_route=\/wp\/v2\/posts\/3993\/revisions\/7691"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/physikon.net\/index.php?rest_route=\/wp\/v2\/media\/4015"}],"wp:attachment":[{"href":"http:\/\/physikon.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3993"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/physikon.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3993"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/physikon.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3993"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}