Recently, the discovery of room-temperature superconductivity (SC) was experimentally realized in the fcc phase of LaH10 under megabar pressures. This SC of compressed LaH10 has been explained in terms of strong electronphonon coupling (EPC), but the detailed nature of how the large EPC constant and high superconducting transition temperature Tc are attained has not yet been clearly identified. Based on the density-functional theory and the MigdalEliashberg formalism, we reveal the presence of two nodeless, anisotropic superconducting gaps on the Fermi surface (FS). Here, the small gap is mostly associated with the hybridized states of H s and La f orbitals on the three outer FS sheets, while the large gap arises mainly from the hybridized state of neighboring H s or p orbitals on the one inner FS sheet. Further, we find that compressed YH10 with the same sodalitelike clathrate structure has the two additional FS sheets, enhancing EPC constant and Tc. It is thus demonstrated that the nature of room temperature SC in compressed LaH10 and YH10 features the multiband pairing of hybridized electronic state with large EPC constants. https://journals.aps.org/prb/abstract/10.1103/PhysRevB.101.104506
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PhysRevB.101.104506.pdf
Multiband nature of room-temperature superconductivity in LaH10 at high pressure
