发表机构
National Institute of Standards and Technology（美国国家标准与技术研究院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究提出一个多阶段可解释工作流，利用谱矩描述符优先筛选高压二元氢化物超导体，并在50 GPa下发现动态稳定的NaH$_6$，其谐波Allen-Dynes估计$T_c$约230 K。
AI 中文摘要
高压下的富氢材料是常规声子介导超导性的候选材料，但第一性原理电子-声子耦合（EPC）计算在计算上要求很高。我们开发了一个可解释的多阶段工作流程，用于在完整EPC计算之前对二元氢化物超导体进行优先级排序。使用200 GPa下受控的立方$X_m$H$_n$原型，我们引入谱矩$A_1$作为电子-声子扰动强度的中间度量。在其基于线宽的构造中，$A_1$在谐波声子软化时保持有限，从而允许筛选具有虚谐波模式的相关结构；它并不确立不稳定结构的超导性或物理可实现性。对于动态稳定的立方系统，$A_1$与费米能级处的H-$1s$态密度分数$\alpha$、投影费米表面描述符$\beta$和原子数密度$\rho$强相关。这些趋势通过$A_1\approx h\alpha\beta\rho$启发式总结，其中$h$取决于框架和压力；该描述符用于排序，而非作为通用的$T_c$预测器。我们将$\alpha\beta\rho$和焓竞争力纳入一个三阶段进化搜索，包括多目标结构筛选、谐波声子稳定性过滤和粗粒度密度泛函微扰理论（DFPT）EPC计算。应用于50和200 GPa下超过100,000个二元氢化物结构，识别出候选物并优先考虑NaH$_6$结构族。更高精度的计算表明，$Pm\bar{3}m$ NaH$_6$在低至50 GPa时动态稳定，谐波Allen-Dynes估计$T_c\approx230$~K。该框架结合电子描述符与逐步更昂贵的稳定性和EPC计算，用于可扩展的氢化物探索。
英文摘要
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 $X_m$H$_n$ 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 $A_1\approx hαβρ$, 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 $Pm\bar{3}m$ NaH$_6$ is dynamically stable down to 50~GPa and has a harmonic Allen--Dynes estimate of $T_c\approx230$~K. The framework combines electronic descriptors with progressively more expensive stability and EPC calculations for scalable hydride exploration.
