Improved Ab Initio DFT + DMFT with a Density Matrix Renormalization Group Impurity Solver

Strongly correlated electron systems exhibit emergent properties and phase transitions that cannot be captured within conventional band theory. Ab initio methods, such as density functional theory (DFT) in its LDA or GGA approximations, face severe limitations when localized orbitals dominate the physics, since they fail to describe strong local interactions. Dynamical Mean-Field Theory (DMFT) has become a reliable approach to address these systems. In practice, its combination with DFT has already shown substantial improvements in describing the electronic structure of correlated materials. The core of DMFT lies in the self-consistent solution of a quantum impurity problem, where the choice of solver is critical. Among the most accurate solvers is the Density Matrix Renormalization Group (DMRG). Unlike other techniques, DMRG works directly on the real frequency axis and can operate at zero temperature, avoiding analytical continuation and providing superior spectral resolution. In this work we present how the combination of DMFT and DMRG improves ab initio calculations for strongly correlated systems.