סמינר בפיזיקה כימית: Efficient hybrid and screened hybrid functionals in real-space

Abstract:

Density Functional Theory (DFT) with hybrid (e.g., PBE0 or B3LYP) and screened hybrid (e.g., HSE or BNL) functionals provide a good balance between computational cost and the ability to predict realistic electronic properties of molecules and solid materials. Even with such approximate methods, the calculation of systems of hundreds of atoms becomes a difficult task. Following some motivating examples and a brief review of hybrid functionals in DFT, I will present how we use projection and other schemes to make this task feasible in the real-space formalism where the orbitals are sampled on a grid. This solution will be presented for both molecules and solids, where Bloch symmetry is applied. I will review some possible strategies to achieve linear scaling and finally give examples of graphene flakes and silicon quantum dots that we calculated with this method.