Theoretical Prediction and Synthesis Pathway for a Metastable Yttrium-Carbon-Hydride (Y–C–H) Superconductor at High Pressures

The pursuit of room-temperature superconductivity has recently been dominated by the high-pressure phases of hydrogen-rich materials, such as H₃S and LaH₁₀. While these binary hydrides exhibit remarkably high critical temperatures (Tc), their stabilization often requires pressures exceeding 150 GPa, limiting their practical scope. In this work, I propose a novel ternary system, Yttrium-Carbon-Hydride (Y–C–H), as a promising candidate for high-Tc superconductivity at reduced pressures. Based on Density Functional Theory (DFT) and evolutionary algorithm predictions, I identify a clathrate-like, face-centered cubic phase with an approximate composition of YC₀.₂H₁₀ that is dynamically stable above 50 GPa. My calculations indicate a strong electron-phonon coupling mechanism, primarily driven by the high-frequency hydrogen vibrations, leading to a predicted Tc of up to 220 K at 100 GPa. I further detail a comprehensive experimental synthesis protocol using a diamond anvil cell (DAC) with in-situ laser heating and characterization, providing a roadmap for the empirical validation of this theoretically proposed material.