Full cell quantum embedding for photoexcitations in correlated solid-state materials

The quant. prediction of photoemission spectra in correlated solid-state materials requires simulations without empirical truncations and parameters. We present a method to achieve this goal through a new ab initio formulation of quantum embedding. Instead of using small impurities defined in a low-energy subspace, which require complicated downfolded interactions which are often approximated, we describe the full cell dynamical mean-field theory (DMFT), where the impurities comprise all atoms in a unit cell or supercell of the crystal. Our formulation results in large impurity problems, which we treat here with efficient quantum chem. impurity solvers such as the coupled-cluster theory and DMRG, combined with a GW treatment of long-range interactions. We apply our method to study correlated transition metal oxides, including nickel oxide, hematite and cuprate superconductors, and show calcd. photoemission spectrum results.