Design of a 60.8 K superconducting hydride LiMgZr2H12 at ambient pressure via Lithium doping

TL;DR

This paper reports the design of a lithium-doped hydride superconductor, LiMgZr2H12, which is predicted to be superconducting at 60.8 K under ambient pressure, offering a promising alternative to high-pressure superconductors.

Contribution

The study introduces a novel ambient-pressure hydride superconductor, LiMgZr2H12, with enhanced superconducting properties through lithium doping, based on first-principles calculations.

Findings

LiMgZr2H12 has a Tc of 60.8 K at ambient pressure.

Lithium doping increases hydrogen's contribution to the density of states.

LiMgZr2H12 shows a superconducting figure of merit of 1.56.

Abstract

High-pressure hydrogen-rich compounds have long been regarded as promising room-temperature superconductor candidates; however, their practical applications are limited by their reliance on extreme compression. This study explores hydrogen-rich superconductors that may be stable at ambient pressures. Inspired by recent investigations of the MgZrH2n family, the LiMgZr2H12 structure with a Pmmm symmetry was constructed, and its thermodynamic, mechanical, and dynamical stability were evaluated using first-principles calculations. Electron-phonon coupling (EPC) analysis suggests that LiMgZr2H12 reaches a superconducting critical temperature (Tc) of 60.8 K at ambient pressure. Compared with MgZrH6, Li doping significantly increases the contribution of hydrogen atoms to the electron density of states near the Fermi level (EF) and enhances the EPC constant of the LiMgZr2H12 structure. LiMgZr2H12 exhibits a superconducting figure of merit of 1.56, which is significantly greater than that of MgZrH6, demonstrating its outstanding potential for practical applications. This work guides ambient-pressure design of high-Tc hydrides.