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O: Fachverband Oberflächenphysik

O 92: Electronic Structure Theory

O 92.2: Vortrag

Donnerstag, 20. März 2025, 15:15–15:30, H25

Automated Wannier functions inspired by topological quantum chemistry — •Stepan S. Tsirkin — Centro de Física de Materiales, San Sebastián, Spain

Despite Wannier functions (WFs) becoming a popular and powerful technique for studying diverse electronic properties of materials, the construction of high-quality WFs remains a non-trivial task, often requiring manual intervention and expertise, which obstructs high-throughput calculations using WF-based methods.

I present an approach for selecting initial projections for Wannier functions based on the symmetry indicators of DFT bandsstructure. The initial projections are searched among the possible orbitals at the Wyckoff positions of the crystal, referred to as Elementary Band Representations in the terminology of Topological Quantum Chemistry [Nature 547, 298 (2017)]. Thus, the projections are by construction compatible with the symmetry of the bands, making them suitable for the construction of symmetry-adapted WFs (SAWFs) [Sakuma, PRB 87, 235109 (2013)]. This approach has been implemented in the codes WannierBerri (WB) [NPJ Comput. Mater. 7, 33 (2021)] and IrRep [CPC 272, 108226 (2022)]. Additionally, WannierBerri now implements the construction of SAWFs without several limitations found in the corresponding implementation in Wannier90. In particular, WB can handle spin-orbit coupling, a frozen window, and is compatible with multiple DFT codes (VASP, Quantum Espresso, Abinit, etc.).

This method does not require manual inspection on bands, which makes it suitable for high-throughput calculations.

Keywords: Wannier functions; Ab initio; topology; Electronic structure theory