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TT: Fachverband Tiefe Temperaturen
TT 62: Focus Session: High Temperature Superconductivity in Hydrides
TT 62.2: Invited Talk
Thursday, March 10, 2016, 10:00–10:30, H20
Conventional superconductivity at 203 K at high pressures — Alexander Drozdov1, •Mikhail Eremets1, Ivan Troyan1, Vadim Ksenofontov2, and Sergii Shylin2 — 11Max-Planck-Institut fuer Chemie, Hahn-Meitner-Weg 1, 55128 Mainz, Germany — 2Institut fuer Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universitet Mainz, Staudingerweg 9, 55099 Mainz, Germany.
A search for high, room temperature conventional superconductivity is promising as the Bardeen-Cooper-Schrieffer (BCS) theory in the Eliashberg formulation puts no apparent limits on Tc. Materials with light elements are especially favorable as they provide high frequencies in the phonon spectrum. However only a moderately high Tc = 39 K has been found in this search in MgB2. We systematically studied metallic hydrogen and covalent hydrogen dominant compounds and found the record Tc of 203 K at pressure 140 GPa in sulfur hydride [1]. We proved occurrence of superconductivity by the sharp drop of the resistivity to zero; the decrease of Tc with magnetic field; the pronounce isotope shift of Tc in D2S which evidences of a major role of phonons in the superconductivity; and the magnetic susceptibility measurements. The X-ray diffraction data confirmed that the superconductive phase has the predicted bcc structure. This phase can be considered as an atomic hydrogen superconductor stabilized by sulfur.
A. P. Drozdov, M. I. Eremets, I. A. Troyan, V. Ksenofontov,
S. I. Shylin, Nature 525, 73 (2015)