Ab-Initio self-energy embedding for the photoemission spectra of NiO and MnO

Abstract

The accurate ab-initio simulation of periodic solids with strong correlations is one of the grand challenges of condensed matter. While mature methods exist for weakly correlated solids, the abinitio description of strongly correlated systems is an active field of research. In this work, we show results for the single particle spectral function of the two correlated d-electron solids NiO and MnO from self-energy embedding theory. Unlike earlier work, the theory does not use any adjustable parameters and is fully ab-initio, while being able to treat both the strong correlation and the nonlocal screening physics of these materials. We derive the method, discuss aspects of the embedding and choices of physically important orbitals, and compare our results to x-ray and angle-resolved photoemission spectroscopy as well as bremsstrahlung-isochromat spectroscopy.

Sparse modeling of large-scale quantum impurity models with low symmetries

“…Quantum embedding theories circumvent the need for exponential scaling by mapping the entire computationally intractable system onto an auxiliary impurity model of correlated orbitals embedded in a bath of noninteracting electrons. Examples of this methodology are the dynamical mean-field theory (DMFT) [1], GW +DMFT [2], nonlocal extensions of DMFT [3,4], and the self-energy embedding theory [5,6].…”