Systematic Improvability in Quantum Embedding for Real Materials

Quantum embedding methods have become powerful tools to overcome the deficiencies of traditional quantum modeling in materials science. However, while these are systematically improvable in principle, in practice it is rarely possible to achieve rigorous convergence and often necessary to employ empirical parameters. Here, we formulate a quantum embedding theory, building on the methods of density-matrix embedding theory combined with local correlation approaches from quantum chemistry, to ensure the ability to systematically converge properties of real materials with accurate correlated wave-function methods controlled by a single, rapidly convergent parameter. By expanding supercell size, basis set, and the resolution of the fluctuation space of an embedded fragment, we show that the systematic improvability of the approach yields accurate structural and electronic properties of realistic solids without empirical parameters, even across changes in geometry. The results are presented in insulating, semimetallic, and more strongly correlated regimes, finding state-of-the-art agreement with experimental data.