Heusler-based topological quantum catalyst Fe2VAl with obstructed surface states for the hydrogen-evolution reaction

Topological materials are widely esteemed for their surface metallic states and remarkable carrier mobility, making them effective catalysts for heterogeneous processes. This study showcases the outstanding properties of Fe₂VAl, an experimentally prepared compound that enjoys a Cu₂MnAl-type Heusler structure. It specifically highlights the presence of robust obstructed surface states on the (001) surface and the outstanding catalytic effectiveness of the compound in electrochemical hydrogen evolution processes (HER). The band structure calculation in this work shows that it is an obstructed atomic semimetal with a pseudo-gap of −0.088 eV (nearly −0.1 eV). These findings align with the previous optical conductivity measurements conducted at low temperatures, which also showed a similar pseudo-gap. This work suggests that the easily prepared Fe₂VAl compound may be an excellent topological quantum material for topological catalysis.