Density Matrix Embedding Theory: From Lattice Models to Realistic Materials

In the past few years, density matrix embedding theory (DMET) [Phys. Rev. Lett. 109, 186404] has emerged as a successful wavefunction-based embedding scheme for both lattice models and molecules, but with few applications to ab initio periodic Hamiltonians. In this work, we will discuss a unified formalsim for both lattice models and realistic solids. We will highlight some practical considerations in the simulation of realistic materials with DMET, including the choice of orbitals and mapping to a lattice, treatment of the virtual space and bath truncation, and the lattice-to-embedded integral transformation. We apply our DMET framework to both Hubbard-like lattice models and several realitic materials, e.g. hexagonal boron nitride monolayer, crystalline silicon, and nickel monoxide in the antiferromagnetic phase, using large embedded clusters with up to 300 embedding orbitals.