Potential high- Tc superconducting lanthanum and yttrium hydrides at high pressure

Hanyu Liu; Ivan I Naumov; Roald Hoffmann; N W Ashcroft; Russell J Hemley

doi:10.1073/pnas.1704505114

Potential high- T_c superconducting lanthanum and yttrium hydrides at high pressure

Proc Natl Acad Sci U S A. 2017 Jul 3;114(27):6990-6995. doi: 10.1073/pnas.1704505114. Epub 2017 Jun 19.

Authors

Hanyu Liu¹, Ivan I Naumov¹, Roald Hoffmann², N W Ashcroft³, Russell J Hemley^{4

5}

Affiliations

¹ Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015.
² Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853.
³ Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853.
⁴ Department of Civil and Environmental Engineering, The George Washington University, Washington, DC 20052; rhemley@gwu.edu.
⁵ School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853.

Abstract

A systematic structure search in the La-H and Y-H systems under pressure reveals some hydrogen-rich structures with intriguing electronic properties. For example, LaH₁₀ is found to adopt a sodalite-like face-centered cubic (fcc) structure, stable above 200 GPa, and LaH₈ a C2/m space group structure. Phonon calculations indicate both are dynamically stable; electron phonon calculations coupled to Bardeen-Cooper-Schrieffer (BCS) arguments indicate they might be high-T_c superconductors. In particular, the superconducting transition temperature T_c calculated for LaH₁₀ is 274-286 K at 210 GPa. Similar calculations for the Y-H system predict stability of the sodalite-like fcc YH₁₀ and a T_c above room temperature, reaching 305-326 K at 250 GPa. The study suggests that dense hydrides consisting of these and related hydrogen polyhedral networks may represent new classes of potential very high-temperature superconductors.

Keywords: high pressure; hydrides; structure search; superconductivity.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.