ScholarWorks@성균관대학교

초록

Pt–Sr binary intermetallics encompass a broad range of stoichiometries and crystal structures, stabilized by complex bonding and multivalent chemistry. The Sr-rich end member, PtSr<inf>5</inf>, was recently identified via artificial-intelligence–guided materials design as a body-centered tetragonal compound (I4/m) [1]. Using first-principles calculations, we show that PtSr<inf>5</inf> hosts a Dirac semimetal phase with trivial Z<inf>2</inf> topology, classified as a normal Dirac semimetal. A symmetry-indicator analysis based on parity eigenvalues at the eight time-reversal-invariant momenta confirms that all Z<inf>2</inf> invariants—evaluated on time-reversal-invariant two-dimensional subspaces of momentum space with a direct band gap—are trivial, thereby establishing the topologically trivial nature of the Dirac semimetal phase. Nonetheless, our calculations reveal that applying an external Zeeman magnetic field along the z-axis drives the system into a Weyl semimetal phase, as corroborated by characteristic changes in the computed surface states. This work demonstrates the tunability of topological phases in PtSr<inf>5</inf> via external perturbations and highlights the effectiveness of AI-based materials exploration in discovering new quantum materials. © 2025 Elsevier B.V., All rights reserved.

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