Sonlu elemanlar yöntemiyle yoğunluk fonksiyoneli pertürbasyon teorisi üzerine

Density Functional Perturbation Theory (DFPT) introduces a systematic framework to compute higher-order material properties based on Density Functional Theory (DFT) and linear response theory. However, most conventional implementations are intrinsically formulated for periodic structures, which may obscure flexibility of complex systems. In order to overcome the limitations, DFPT is reformulated for the first time within Finite Element Method (FEM), a real-space method. The models are developed for both all-electron and pseudopotential frameworks with the GGA and LDA exchange-correlation functionals. For aperiodic system implementations, benchmark calculations achieved chemical accuracy.