Superconductivity in CaH and ThH through fully ab initio Eliashberg method and self-consistent Green's function.

Pressurized hydrogen-based superconductors are phonon-mediated superconductors that exhibit high phonon frequencies. In these superconductors, in addition to the density of states (DOS) at the Fermi energy ( ), the energy dependence of the DOS around becomes important for evaluating their transition temperature ( ). Systems with peak structures in the DOS around , such as H S and LaH , highlight this point. We use the fully ab initio Eliashberg method to investigate this phenomenon in CaH and ThH with a dip structure in their DOS around . Our calculated values (225-235 K for CaH at 200 GPa and 156-158 K for ThH at 170 GPa) are quantitatively consistent with the experimental results. Remarkably, our results from the self-consistent treatment of the electron Green's function contrasts with those cases with a peak structure in the DOS. This finding unifies the understanding of how DOS structures influence the evaluation of .