Effect of doping on the phase stability and superconductivity in LaH10

We present a computational investigation into the effects of chemical doping with 15 different elements on phase stability and superconductivity in the $\mathrm{La}{\mathrm{H}}_{10}$ structure. Most doping elements were found to induce softening of phonon modes, enhancing electron-phonon coupling and improving critical superconducting temperature while weakening dynamical stability. Unlike these dopants, Ce was found to extend the range of dynamical stability for $\mathrm{La}{\mathrm{H}}_{10}$ by eliminating the Van Hove singularity near the Fermi level. The doped compound, ${\mathrm{La}}_{0.75}{\mathrm{Ce}}_{0.25}{\mathrm{H}}_{10}$, maintains high-temperature superconductivity. We also demonstrate that different Ce doping configurations in the $\mathrm{La}{\mathrm{H}}_{10}$ structure have a minimal effect on energetic stability and electron-phonon coupling strength. Our findings suggest that Ce is a promising dopant to stabilize $\mathrm{La}{\mathrm{H}}_{10}$ at lower pressures while preserving its high-temperature superconductivity.