Enhanced Coulomb pseudopotentials in high-pressure hydrides from first principles
Abstract
In the Eliashberg theory of superconductivity, Coulomb interactions oppose the phonon-mediated attraction and suppress the superconducting critical temperature Tc. However, most first-principles predictions continue to treat this repulsion with an empirical Coulomb pseudopotential μ*ME in the range 0.1-0.15. Here we present first-principles calculations of the Coulomb parameter μ and pseudopotential μ*ME in superconducting hydrides across a range of pressures. The screened Coulomb interaction is evaluated at the random phase approximation level with the Mantel code. We demonstrate that several hydride systems, including H3S, YSbH6 and Mg2IrH6, have strong Coulomb repulsions driven by a large density of states at the Fermi energy, NF. For Mg2IrH6 we obtain μ=0.62 and μ*ME≈0.39, leading to a 40 K suppression in Tc relative to a standard μ*ME=0.16. Our obtained μ*ME is far above the conventional range and, accounting for the energy dependence of the density of states, resolves the factor-of-two discrepancy between Tc estimates of previous studies. Across all systems and pressures studied, we find that μ closely tracks NF, suggesting that commonly used μ*ME values lead to overestimated Tc in materials where the density of states at the Fermi energy is large.
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BibTeX
@misc{bozier2026enhanced,
title = {{Enhanced Coulomb pseudopotentials in high-pressure hydrides from first principles}},
author = {Kieran Bozier and Chris J. Pickard},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.12563},
eprint = {2610.12563},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.12563},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Enhanced Coulomb pseudopotentials in high-pressure hydrides from first principles
AU - Kieran Bozier
AU - Chris J. Pickard
PY - 2026
DA - 2026/10/08
PB - arXiv
DO - 10.48550/arxiv.2610.12563
UR - https://arxiv.org/abs/2610.12563
AB - In the Eliashberg theory of superconductivity, Coulomb interactions oppose the phonon-mediated attraction and suppress the superconducting critical temperature T_c. However, most first-principles predictions continue to treat this repulsion with an empirical Coulomb pseudopotential μ^*_ME in the range 0.1-0.15. Here we present first-principles calculations of the Coulomb parameter μ and pseudopotential μ^*_ME in superconducting hydrides across a range of pressures. The screened Coulomb interaction is evaluated at the random phase approximation level with the Mantel code. We demonstrate that several hydride systems, including H_3S, YSbH_6 and Mg_2IrH_6, have strong Coulomb repulsions driven by a large density of states at the Fermi energy, N_F. For Mg_2IrH_6 we obtain μ=0.62 and μ^*_ME≈0.39, leading to a 40 K suppression in T_c relative to a standard μ^*_ME=0.16. Our obtained μ^*_ME is far above the conventional range and, accounting for the energy dependence of the density of states, resolves the factor-of-two discrepancy between T_c estimates of previous studies. Across all systems and pressures studied, we find that μ closely tracks N_F, suggesting that commonly used μ^*_ME values lead to overestimated T_c in materials where the density of states at the Fermi energy is large.
ER -