Superconductivity of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>LaH</mml:mi><mml:mn>10</mml:mn></mml:msub></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>LaH</mml:mi><mml:mn>16</mml:mn></mml:msub></mml:math> polyhydrides
Ivan A. Kruglov, Dmitrii V. Semenok, Hao Song, R. Szczȩśniak, Izabela A. Wrona, Ryosuke Akashi, M. Mahdi Davari Esfahani, Defang Duan, Tian Cui, Alexander G. Kvashnin, Artem R. Oganov
Abstract
Recent experiments have established previously predicted ${\mathrm{LaH}}_{10}$ as the highest-temperature superconductor, with ${T}_{C}$ up to 250--260 K [Drozdov et al., Nature (London) 569, 528 (2019); Somayazulu et al., Phys. Rev. Lett. 122, 027001 (2019)]. In this work we explore the high-pressure phase stability and superconductivity of lanthanum hydrides ${\mathrm{LaH}}_{m}$. We predict the stability of the hitherto unreported polyhydride $P6/mmm\ensuremath{-}{\mathrm{LaH}}_{16}$ at pressures above 150 GPa; at 200 GPa, its predicted superconducting ${T}_{C}$ is 156 K, the critical field ${\ensuremath{\mu}}_{0}{H}_{C}(0)$ is approximately 35 T, and the superconducting gap is up to 35 meV. We revisit the superconductivity of ${\mathrm{LaH}}_{10}$ and find its ${T}_{C}$ to be up to 259 K at 170 GPa from solving the Eliashberg equation and 271 K from solving the gap equation within the superconducting density functional theory, which also allows us to compute the Coulomb pseudopotential ${\ensuremath{\mu}}^{*}$ for ${\mathrm{LaH}}_{10}$ and ${\mathrm{LaH}}_{16}$.