Multiband nature of room-temperature superconductivity in <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> at high pressure
Chongze Wang, Seho Yi, Jun‐Hyung Cho
Abstract
Recently, the discovery of room-temperature superconductivity (SC) was experimentally realized in the fcc phase of ${\mathrm{LaH}}_{10}$ under megabar pressures. This SC of compressed ${\mathrm{LaH}}_{10}$ has been explained in terms of strong electron-phonon coupling (EPC), but the detailed nature of how the large EPC constant and high superconducting transition temperature ${T}_{\mathrm{c}}$ are attained has not yet been clearly identified. Based on the density-functional theory and the Migdal-Eliashberg 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 ${\mathrm{YH}}_{10}$ with the same sodalitelike clathrate structure has the two additional FS sheets, enhancing EPC constant and ${T}_{\mathrm{c}}$. It is thus demonstrated that the nature of room-temperature SC in compressed ${\mathrm{LaH}}_{10}$ and ${\mathrm{YH}}_{10}$ features the multiband pairing of hybridized electronic states with large EPC constants.