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Lanthanum hydride LaH$_{10}$ with a sodalitelike clathrate structure was experimentally realized to exhibit a room-temperature superconductivity under megabar pressures. Based on first-principles calculations, we reveal that the metal framework of La atoms has the excess electrons at interstitial regions. Such anionic electrons are easily captured to form a stable clathrate structure of H cages. We thus propose that the charge transfer from La to H atoms is mostly driven by the electride property of the La framework. Further, the interaction between La atoms and H cages induces a delocalization of La-5$p$ semicore states to hybridize with H-1$s$ state. Consequently, the bonding nature between La atoms and H cages is characterized as a mixture of ionic and covalent. Our findings demonstrate that anionic and semicore electrons play important roles in stabilizing clathrate H cages in LaH$_{10}$, which can be broadly applicable to other high-pressure rare-earth hydrides with clathrate structures.
Intuitively, doping represents one of the most promising avenues for optimization of best prospect superconductors (SC) such as conventional high-pressure SCs with record critical temperatures. However, doping at high pressure (HP) is very challengin
Recently, the discovery of room-temperature superconductivity (SC) was experimentally realized in the fcc phase of LaH$_{10}$ under megabar pressures. This SC of compressed LaH$_{10}$ has been explained in terms of strong electron-phonon coupling (EP
Room-temperature superconductivity has been one of the most challenging subjects in modern physics. Recent experiments reported that lanthanum hydride LaH$_{10{pm}x}$ ($x$$<$1) raises a superconducting transition temperature $T_{rm c}$ up to ${sim}$2
The vision of ``room temperature superconductivity has appeared intermittently but prominently in the literature since 1964, when W. A. Little and V. L. Ginzburg began working on the `problem of high temperature superconductivity around the same time
We report pair distribution function measurements of the iron-based superconductor FeSe above and below the structural transition temperature. Structural analysis reveals a local orthorhombic distortion with a correlation length of about 4 nm at temp