Evidence of Molecular Hydrogen in the N-doped LuH<sub>3</sub> System

Cesare Tresca, Pietro Maria Forcella, Andrea Angeletti, Luigi Ranalli, Cesare Franchini, Michele Reticcioli, Gianni Profeta

The report of near-ambient superconductivity in nitrogen-doped lutetium hydrides could represent an epochal discovery, awaited for more than a century, possibly leading to inconceivable scientific and technological implications. However, after months since the first report, clear experimental and theoretical confirmations are yet to come: The initially proposed compound structure fails to explain the superconducting behavior, calling for a shift in perspective. By means of machine-learning-accelerated force-field molecular dynamics, we explore the formation of H2 molecules in nitrogen-doped lutetium hydride, demonstrating the active role of nitrogen in stabilizing this phase. Our density functional theory calculations show that the presence of hydrogen molecules leads to a dynamically stable structure, characterized by a superconducting phase requiring no applied pressure, although the predicted temperatures are still much lower than room temperature. We believe that the possibility to stabilize hydrogen in molecular form represents a new route to explore disordered phases in hydrides and their transport properties at near ambient conditions.

Computational and Soft Matter Physics, Computational Materials Physics
Publication date
Austrian Fields of Science 2012
103009 Solid state physics
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