Charge self-consistency

The DFT-driver framework and the charge-density correction that close the charge self-consistent DFT+DMFT (CSC) loop. This is the generic DFT driver framework that abstracts the DFT electronic-structure code from ModEST.

For more details on specific drivers of DFT electronic structure codes, please see TRIQS/dftkit.

Generic DFT driver framework

triqs_modest.dft_driver.DftDriver(...)

Charge-density correction

The charge-density correction is the band-resolved density matrix of the interacting (DMFT-corrected) Green’s function, expressed in the Kohn–Sham basis:

\[N_{\nu\nu'}^{\sigma}(\mathbf{k}) = \frac{1}{\beta}\sum_{n}\, \bigl[G_{\mathcal{B}}^{\sigma}(\mathbf{k}, i\omega_n)\bigr]_{\nu\nu'}\, e^{i\omega_n 0^{+}},\]

with \(G_{\mathcal{B}}^{\sigma}\) the lattice Green’s function of (3). In a CSC iteration, ModEST hands the deviation from the Kohn–Sham density,

\[\Delta N_{\nu\nu'}^{\sigma}(\mathbf{k}) = N_{\nu\nu'}^{\sigma}(\mathbf{k}) - n_{F}\bigl(\varepsilon_{\nu}^{\sigma}(\mathbf{k}) - \mu\bigr)\, \delta_{\nu\nu'},\]

back to the DFT code as the correction to the KS density.

triqs_modest.local_gf.charge_density_correction

Compute the charge density correction from DMFT