2015/02/28 by Ryosuke Akashi, Mitsuaki Kawamura, Shinji Tsuneyuki +2 · 1 citation
Physics and Astronomy · #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.91.224513
published as Phys. Rev. B 91, 224513 (2015) · Main text: 6 pages, 3 figures, 1 table. Supplemental Material: 3 pages, 6 tables. Comment on ver2: Supplemental Material has been merged with the main text, data have been added in Fig.1, and the title has been changed from the original version
arxiv created 2015/07/07 · arxiv updated 2015/07/08
We calculate superconducting transition temperatures (T\rm c) in sulfur hydrides H2S and H3S from first principles using the density functional theory for superconductors. At pressures of \lesssim150 GPa, the high values of T\rm c (\gtrsim130 K) observed in the recent experiment [A. P. Drozdov, M. I. Eremets, and I. A. Troyan, arXiv:1412.0460] are accurately reproduced by assuming that H2S decomposes into R3m-H3S and S. For the higher pressures, the calculated T\rm cs for Im3m-H3S are systematically higher than those for R3m-H3S and the experimentally observed maximum value (190 K), which suggests the possibility of another higher-T\rm c phase. We also quantify the isotope effect from first principles and demonstrate that the isotope effect coefficient can be larger than the conventional value (0.5) when multiple structural phases energetically compete.