Category:Electronic occupancy

Within the PAW method there is the occupation [math]\displaystyle{ f_k }[/math] for the plane-wave part and the on-site occupation matrix [math]\displaystyle{ \rho }[/math] that characterize the electronic state. Below we list tags and sections that can be used to influence the occupation, besides the obvious influence of the specific structure and exchange-correlation effects.

Theory

Density Functional Theory plus Dynamical Mean Field Theory

Density Functional Theory plus Dynamical Mean Field Theory (DFT+DMFT)^[1] is an advanced extension of DFT that provides a more accurate treatment of strongly correlated materials compared to DFT+U. While DFT+U incorporates a static correction for localized electron interactions, DFT+DMFT goes further by treating these interactions dynamically, capturing frequency-dependent electron correlations. A key feature of DFT+DMFT is that the charge density is updated using the DMFT solution, ensuring a self-consistent feedback between the correlated electronic states and the DFT potential. This not only improves the description of phenomena like metal-insulator transitions and quasiparticle renormalization but also allows for the calculation of spectral properties such as photoemission spectra, transport properties, and total energies relevant to structural distortions. To facilitate DFT+DMFT calculations, VASP provides a general interface to DMFT codes, allowing occupation updates ICHARG=5 via an external file vaspgamma.h5 / GAMMA to update the charge density.

How to

Practical guides to different methods manipulating occupations in VASP are found on following pages:

• DFT+DMFT calculations: example of performing DFT+DMFT calculations using the TRIQS software^[2]

References