{"id":3717,"date":"2017-02-08T14:43:53","date_gmt":"2017-02-08T22:43:53","guid":{"rendered":"http:\/\/physikon.net\/?p=3717"},"modified":"2022-06-22T09:37:36","modified_gmt":"2022-06-22T16:37:36","slug":"on-the-isotope-effect-in-compressed-superconducting-h3s-and-d3s","status":"publish","type":"post","link":"http:\/\/physikon.net\/?p=3717","title":{"rendered":"On the Isotope Effect in Compressed Superconducting H3<\/sub>S and D3<\/sub>S"},"content":{"rendered":"

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On the Isotope Effect in Compressed Superconducting H3<\/sub>S and D3<\/sub>S<\/strong>, D. R. Harshman and A. T. Fiory [arXiv<\/a>]\n

A maximum superconductive transition temperature T<\/em>C<\/sub> = 203.5 K has recently been reported for a sample of the binary compound tri-hydrogen sulfide (H3<\/sub>S) prepared at high pressure and with room temperature annealing.\u00a0 Measurements of T<\/em>C<\/sub> for H3<\/sub>S and its deuterium counterpart D3<\/sub>S have suggested a mass isotope effect exponent \u03b1 with anomalous enhancements for reduced applied pressures.\u00a0 While widely cited for evidence of phonon-based superconductivity, the measured T<\/em>C<\/sub> is shown to exhibit important dependences on the quality and character of the H3<\/sub>S and D3<\/sub>S materials under study; examination of resistance vs<\/em>. temperature data shows that variations in T<\/em>C<\/sub> and apparent \u03b1 are strongly correlated with residual resistance ratio, indicative of sensitivity to metallic order.\u00a0 Correlations also extend to the fractional widths of the superconducting transitions.\u00a0 Using resistance data to quantify and compensate for the evident materials differences between H3<\/sub>S and D3<\/sub>S samples, a value of \u03b1 = 0.043 \u00b1 0.140 is obtained.\u00a0 Thus, when corrected for the varying levels of disorder, the experimental upper limit (\u22640.183) lies well below \u03b1 derived in phonon-based theories.<\/p>\n

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Transition temperatures T<\/em>C<\/sub> for H3<\/sub>S (green circles) and D3<\/sub>S (blue circles) vs. applied pressure P with corresponding dashed lines fitted to joined linear trends using equation (1) of the article with parameters in table 1 of the article (left scale). Residual resistance ratios RRR are shown for H3<\/sub>S (red triangles) and D3<\/sub>S (red diamonds) vs. P (right scale). Data are for samples annealed at or above room temperature (see REfs. [1,2] of the article).<\/p><\/td>\n<\/tr>\n

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Residual resistance ratio RRR vs. fractional transition width ΔT<\/em>C<\/sub>\/T<\/em>C<\/sub> for samples of H3<\/sub>S (green triangles) and D3<\/sub>S (blue diamonds). A linearly fitted dashed line is drawn to indicate the trend.<\/p><\/br><\/td>

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Transition temperature T<\/em>C<\/sub> vs. residual resistance ratio RRR for H3<\/sub>S (green triangles) and D3<\/sub>S (blue diamonds). The eight symbols with dot fill correspond to data for P \u2273 Pm<\/sub> with trend shown by the fitted dashed line.<\/p><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n

Dale R. Harshman and Anthony T. Fiory, Supercond. Sci. and Technol. 30<\/strong>, 045011 (2017)<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":3535,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,29],"tags":[],"class_list":["post-3717","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-high-tc-superconductivity","category-isotope-effect"],"_links":{"self":[{"href":"http:\/\/physikon.net\/index.php?rest_route=\/wp\/v2\/posts\/3717","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=3717"}],"version-history":[{"count":26,"href":"http:\/\/physikon.net\/index.php?rest_route=\/wp\/v2\/posts\/3717\/revisions"}],"predecessor-version":[{"id":7692,"href":"http:\/\/physikon.net\/index.php?rest_route=\/wp\/v2\/posts\/3717\/revisions\/7692"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/physikon.net\/index.php?rest_route=\/wp\/v2\/media\/3535"}],"wp:attachment":[{"href":"http:\/\/physikon.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3717"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/physikon.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3717"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/physikon.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3717"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}