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A. Valli, G. Gandus, D. Passerone, R. Stadler:
"Local orbitals for ab-initio and many-body simulations of nano devices";
Poster: GPAW 2021, Online; 01.06.2021 - 04.06.2021.

Atomic-like orbital function allow for computationally efficient calculations within density functional theory (DFT) although the accuracy is limited by the choice of the basis. At the same time, extensive basis sets pose fundamental problems of interpretation of the results. An alternative is to define local orbitals (LOs) which inherit the information of the local crystal field and have a natural physical interpretation. Moreover, keeping a subset of relevant LOs is sufficient to provide an accurate description of the physics around the Fermi level, reducing to some extent the redundancy of the original basis set. Thus, LOs allow for, e.g., efficient transport calculations without sacrificing accuracy but are also useful to define realistic effective Hamiltonians for many-body calculations. We demonstrate LOs for classes of materials with very different chemical and physical properties and present perspectives for future applications.