Crystal symmetry may determine whether hydrogen inside vanadium behaves like a classical particle or a quantum wave, according to a new study published in Nature Communications. As countries accelerate investment in clean hydrogen energy, safer storage and transport materials are becoming a central challenge. Vanadium stands out because it can absorb hydrogen and allow it to move through its crystal lattice.
Inside the metal, hydrogen migrates by occupying interstitial sites and “hopping” between neighboring positions. The critical question is what governs the transport mechanism: does hydrogen need thermal energy to overcome energy barriers, or can it bypass them through quantum tunneling?
To address this, researchers from the Institute of Industrial Science at The University of Tokyo combined structural and diffusion measurements with quantum mechanical calculations. Their results connect hydrogen mobility directly to the symmetry of the host crystal environment. In other words, the lattice doesn’t merely provide pathways for diffusion—it actively controls the quantum character of hydrogen motion.
At low hydrogen concentrations, the crystal remains highly symmetric. Under these conditions, hydrogen can tunnel between equivalent sites, producing delocalized quantum states that extend across adjacent atomic positions. This quantum “shortcut” increases the probability of movement without requiring conventional barrier crossing.
As hydrogen concentration rises, however, the lattice distorts. That symmetry breaking suppresses tunneling by removing the energetic equivalence and coherence needed for wave-like transport. Hydrogen then transitions toward a behavior dominated by classical hopping, where motion relies more strongly on thermal activation.
The authors describe crystal symmetry as a switch that turns tunneling on or off. In symmetric structures, hydrogen finds balanced pathways; once distortion sets in, those pathways become inequivalent and tunneling efficiency drops.
These findings suggest a practical route to materials engineering: by designing or stabilizing crystal structures with targeted symmetry, developers may tune hydrogen’s transport properties. Such control could improve storage capacity and diffusion management in real-world hydrogen technologies.
Beyond hydrogen, the work provides a broader framework for manipulating quantum effects in solids by controlling structural order and distortions at the atomic scale. That approach may help guide future “quantum-aware” material design for next-generation energy systems.
Subject of Research: Hydrogen diffusion and quantum tunneling in vanadium controlled by crystal symmetry
Article Title: Impact of Crystal Symmetry Lowering on Proton Tunneling
News Publication Date: 15-Jul-2026
Web References: https://doi.org/10.1038/s41467-026-75020-w
References: Nature Communications, DOI: 10.1038/s41467-026-75020-w
Image Credits: Institute of Industrial Science, The University of Tokyo
Keywords
Quantum mechanics; Hydrogen storage; Vanadium; Proton tunneling; Crystal symmetry; Condensed matter physics; Diffusion; Materials science; Energy technologies
