“Tubular” lanthanum hydride: a new class of high-temperature superconducting materials

Quantum calculations within density functional theory have predicted a new structure of lanthanum hydride La$_2$H$_{24}$ that is dynamically stable up to pressures about $150$ GPa. It is a semimetal and has a low symmetry of crystal lattice $P\overline{1}$. An important feature of this structure is the existence of quasimolecular hydrogen chains, which leads to the presence of phonon frequencies of about $420$ meV, exceeding the maximum vibration frequency of the metallic hydrogen $Fddd$ phase ($\omega\sim360$ meV). These properties make it possible to expect a high superconducting transition temperature for lanthanum hydride La$_2$H$_{24}$.