Bulk‐Boundary Correspondence of Semimetal Ru₃Sn₇ and Topological Surface States on Chemically Realistic Terminations

Journal Article · Mon Nov 10 00:00:00 UTC 2025 · Advanced Materials Interfaces

DOI: https://doi.org/10.1002/admi.202500711 · OSTI ID:3020370

Weng, Guorong  ^[1]; Alexandrova, Anastassia N.  ^[2]

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1. University of California, Los Angeles, CA (United States)
2. University of California, Los Angeles, CA (United States); California NanoSystems Institute, Los Angeles, CA (United States)

Ru₃Sn₇ is experimentally demonstrated as an efficient catalyst, with potential utilization of topological surface states for hydrogen evolution reaction. Despite its promising catalytic performance, the topological nature of Ru₃Sn₇ remains uncertain. Particularly, the bulk-boundary correspondence has not yet been established, hence hindering a rigorous justification of its topologically-protected surface states. In this work, the bulk topology of Ru₃Sn₇ is detailed using first-principles calculations and the topological quantum chemistry formalism. Ru3Sn7 turns out to be an enforced semimetal possessing symmetry-protected crossings within a set of bands near the Fermi level, which are enforced and prescribed by the violations of symmetry-prescribed compatibility relations. Moreover, the surface states and the associated origin from the same set of entangled bands are identified, thereby establishing the bulk-boundary correspondence. To evaluate the effects of chemical modifications, the response of topological surface states to various surface terminations, stoichiometry, and oxidation is examined. The surface structures are globally optimized, and the phase diagrams for various experimental conditions are built. It is shown that, due to changes in the local chemical environment, the original surface states are significantly altered. Modified surface bands can be observed near the Fermi level on surface terminations that preserve the C_4v symmetry.

• Research Organization: University of California, Los Angeles, CA (United States)
• Sponsoring Organization: Brown Science Foundation; National Energy Research Scientific Computing Center (NERSC); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-05CH11231; SC0024987
• OSTI ID: 3020370
• Journal Information: Advanced Materials Interfaces, Journal Name: Advanced Materials Interfaces Journal Issue: 23 Vol. 12; ISSN 2196-7350
• Publisher: Wiley-VCHCopyright Statement
• Country of Publication: United States
• Language: English