Regensburg 2019 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 58: Focus Session: Electron-Phonon Interactions II
O 58.3: Vortrag
Mittwoch, 3. April 2019, 15:45–16:00, H15
Superconductivity from first-principles in sodalite yttrium hydrides — •Simone Di Cataldo1, Christoph Heil1, Lilia Boeri2, and Giovanni Bachelet2 — 1Institute of Theoretical and Computational Physics, Graz University of Technology, NAWI Graz, 8010 Graz, Austria — 2Dipartimento di Fisica, Sapienza Università di Roma, 00185 Roma, Italy
The recent experimental discovery of the record-breaking critical superconducting temperature of 265 K in a lanthanum superhydride (LaH10 ), following the one of 203 K in SH3 three years ago, firmly supports hydrides as promising candidates in the search for room-temperature superconductivity.
In our work we use Density Functional Theory, together with fully anisotropic first-principles Migdal-Eliashberg theory to investigate the electronic, vibrational and superconducting properties of two yttrium hydrides (YH6 and YH10), which are closely related to the corresponding lanthanum hydrides, but have been predicted to exhibit even higher Tcs. We show that the superconducting properties are rather uniform over all phonon and electronic states, meaning that the origin of the strong electron-phonon coupling cannot be explained only in terms of the hydrogen sublattice, but is rather due to the interaction between the host atom and the whole clathrate sublattice. A comparison of the pressure behavior of the Tc of the two compounds suggests a route to lower the pressure to high Tc superconductivity.