New superconducting superhydride LaC2H8 at relatively low stabilization pressure

Abstract

Motivated by the recent experimental discovery of high-temperature carbonaceous sulfur hydride (C–S–H), we have systematically explored the superconductivity of a carbonaceous lanthanum hydride (C–La–H) ternary compound in the pressure range of 50–250 GPa. Based on first-principles calculations and strong-coupling Migdal–Eliashberg theory, we find that a hitherto unreported LaC₂H₈ ternary system is dynamically and thermally stable above 70 GPa in a clathrate structure with space group Fmm and exhibits a superconducting critical temperature, T_c, in the range of 69–140 K.