Periodic Trends and a Physics-Based Multistage Search for High-Tc Hydride Superconductors
Abstract
Hydrogen-rich materials under pressure are candidates for conventional phonon-mediated superconductivity, but first-principles electron--phonon-coupling (EPC) calculations are computationally demanding. We develop an interpretable multistage workflow for prioritizing binary hydride superconductors before full EPC calculations. Using controlled cubic XmHn prototypes at 200~GPa, we introduce the spectral moment A1 as an intermediate measure of electron--phonon perturbation strength. In its linewidth-based construction, A1 remains finite as harmonic phonons soften, allowing related structures with imaginary harmonic modes to be screened; it does not establish superconductivity or physical realizability for unstable structures. For dynamically stable cubic systems, A1 correlates strongly with the H-1s density-of-states fraction at the Fermi level, α, a projected Fermi-surface descriptor, β, and atomic number density, ρ. These trends are summarized heuristically by A1≈ hαβρ, where h is framework- and pressure-dependent; the descriptor is used for ranking, not as a universal Tc predictor. We incorporate αβρ and enthalpic competitiveness into a three-stage evolutionary search comprising multiobjective structural screening, harmonic-phonon stability filtering, and coarse density-functional perturbation-theory (DFPT) EPC calculations. Application to more than 100,000 binary hydride structures at 50 and 200~GPa identifies candidates and prioritizes NaH6 structural families. Higher-accuracy calculations show that Pm3̅m NaH6 is dynamically stable down to 50~GPa and has a harmonic Allen--Dynes estimate of Tc≈230~K. The framework combines electronic descriptors with progressively more expensive stability and EPC calculations for scalable hydride exploration.
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BibTeX
@misc{chen2026periodic,
title = {{Periodic Trends and a Physics-Based Multistage Search for High-$T_c$ Hydride Superconductors}},
author = {Tianran Chen and Taner Yildirim},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.35582},
eprint = {2609.35582},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.35582},
}
RIS
TY - UNPB
TI - Periodic Trends and a Physics-Based Multistage Search for High-T_c Hydride Superconductors
AU - Tianran Chen
AU - Taner Yildirim
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.35582
UR - https://arxiv.org/abs/2609.35582
AB - Hydrogen-rich materials under pressure are candidates for conventional phonon-mediated superconductivity, but first-principles electron--phonon-coupling (EPC) calculations are computationally demanding. We develop an interpretable multistage workflow for prioritizing binary hydride superconductors before full EPC calculations. Using controlled cubic X_mH_n prototypes at 200~GPa, we introduce the spectral moment A_1 as an intermediate measure of electron--phonon perturbation strength. In its linewidth-based construction, A_1 remains finite as harmonic phonons soften, allowing related structures with imaginary harmonic modes to be screened; it does not establish superconductivity or physical realizability for unstable structures. For dynamically stable cubic systems, A_1 correlates strongly with the H-1s density-of-states fraction at the Fermi level, α, a projected Fermi-surface descriptor, β, and atomic number density, ρ. These trends are summarized heuristically by A_1≈ hαβρ, where h is framework- and pressure-dependent; the descriptor is used for ranking, not as a universal T_c predictor. We incorporate αβρ and enthalpic competitiveness into a three-stage evolutionary search comprising multiobjective structural screening, harmonic-phonon stability filtering, and coarse density-functional perturbation-theory (DFPT) EPC calculations. Application to more than 100,000 binary hydride structures at 50 and 200~GPa identifies candidates and prioritizes NaH_6 structural families. Higher-accuracy calculations show that Pm3̅m NaH_6 is dynamically stable down to 50~GPa and has a harmonic Allen--Dynes estimate of T_c≈230~K. The framework combines electronic descriptors with progressively more expensive stability and EPC calculations for scalable hydride exploration.
ER -