Superconductivity in LaHeH₈ under High Pressure

The majority of H8-stoichiometry compounds have been explored in the superconducting state. The structural diversity of metal hydrides with H8-stoichiometry provides a remarkable platform for superconductivity. In this context, the high resistance to chemical bond formation remains an open question. To address this, we investigate the superconducting state and structural phase stability of LaHeH8 using ab initio random structure searching under high pressure. Our findings indicate that LaHeH8 attains dynamical stability at 140 GPa. A detailed analysis of chemical bonding reveals weak interactions between La–He and He–H. Based on the semiempirical McMillan's approach, LaHeH8 exhibits superconductivity with a critical temperature (Tc) of approximately 102 K at 140 GPa. These results underscore a promising route for developing novel superconducting materials. Moreover, our study provides valuable insights into enhancing superconductivity through structural modifications, particularly in helium-stabilized LaHeH8.