“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 La2H24 that is dynamically stable up to pressures about 150 GPa. It is a semimetal and has a low symmetry of crystal lattice P1¯\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$P\bar{1}$$\end{document}. 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 (ω ~ 360 meV). These properties make it possible to expect a high superconducting transition temperature for lanthanum hydride La2H24.