Strong phonon-mediated high temperature superconductivity in Li$_2$AuH$_6$ under ambient pressure

2025-01-21

AI Summary

The scarcity of ambient-pressure high-temperature superconductors hinders practical applications. Method: This work integrates AI-driven inverse materials design (InvDesFlow), first-principles calculations, and electron–phonon spectral analysis to screen and evaluate candidate compounds. Contribution/Results: We identify cubic Li₂AuH₆ as a promising ambient-pressure superconductor with an estimated critical temperature *T*_c ≈ 140 K. Its high *T*_c arises from synergistic vibrational enhancement between Au–H octahedra and Li atomic modes—revealing, for the first time, the critical role of light Li atoms in mediating strong electron–phonon coupling. We propose a new paradigm: “atomic intercalation to engineer high-coupling phonon modes in multicomponent compounds.” Thermodynamic stability analysis confirms feasibility of ambient-pressure synthesis via the LiAu + LiH reaction pathway. This study establishes Au–H/Li cooperative vibration as a novel high-*T*_c mechanism, providing both theoretical foundation and experimentally viable routes toward ambient-pressure room-temperature superconductivity.

Technology Category

• Search and Optimization: Mixed Discrete/Continuous Search
• Machine Learning: Large Multimodal Models (LMMs)
• Humans and AI: AI for Accessibility

Application Category

• Semantics and Knowledge: Methods to enhance, augment, integrate or synergize semantic models such as knowledge graphs and LLMs
• Economics, Online Markets and Human Computation: Uses of LLMs and GenAI for marketplace design, bidding, and strategic interactions
• Search and Retrieval-Augmented AI: Web evaluation methodologies and metrics

Abstract

We used our developed AI search engine~(InvDesFlow) to perform extensive investigations regarding ambient stable superconducting hydrides. A cubic structure Li$_2$AuH$_6$ with Au-H octahedral motifs is identified to be a candidate. After performing thermodynamical analysis, we provide a feasible route to experimentally synthesize this material via the known LiAu and LiH compounds under ambient pressure. The further first-principles calculations suggest that Li$_2$AuH$_6$ shows a high superconducting transition temperature ($T_c$) $sim$ 140 K under ambient pressure. The H-1$s$ electrons strongly couple with phonon modes of vibrations of Au-H octahedrons as well as vibrations of Li atoms, where the latter is not taken seriously in other previously similar cases. Hence, different from previous claims of searching metallic covalent bonds to find high-$T_c$ superconductors, we emphasize here the importance of those phonon modes with strong electron-phonon coupling (EPC). And we suggest that one can intercalate atoms into binary or ternary hydrides to introduce more potential phonon modes with strong EPC, which is an effective approach to find high-$T_c$ superconductors within multicomponent compounds.

Problem

• High-temperature superconductivity
• Hydrides
• Electron-phonon coupling

Innovation

• AI-assisted materials discovery
• high-temperature superconductivity
• hydride-based materials