Prediction of Thermodynamically Stable Room‐Temperature Superconductors in Li─Na Hydrides Under High Pressure

Abstract Room‐temperature superconductivity has been a long‐standing goal in the scientific community. For computational predictions, thermodynamic stability plays a critical role. Here, a high‐throughput screening is performed to study high‐pressure ternary clathrate hydrides with hitherto unexplored compositions. Two thermodynamically stable room‐temperature superconductors in the Li─Na─H system, based on the type‐I and type‐II clathrate structure types, both exhibiting superconducting critical temperatures ( T c ’s) exceeding 300 K under high pressure are uncovered. Remarkably, the type‐II structure, Li 2 NaH 17 , exhibits the highest T c of 357 K at 220 GPa among all the reported thermodynamically stable hydrides. Random structure searches show that type‐II clathrate structures can also be stabilized with hydrogen deficiencies which lower the T c . Superconductivity is shown to be the result of a Van‐Hove‐like singularity which can be tuned by the hydrogen content.