Site-occupation Green's function embedding theory: A density functional approach to dynamical impurity solvers

Laurent Mazouin (1) , M. Saubanère (2) , Emmanuel Fromager (1)

1 LCQMM - Laboratoire de chimie quantique et de modélisation moléculaire
2 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier

A reformulation of site-occupation embedding theory (SOET) in terms of Green's functions is presented. Referred to as site-occupation-Green's function embedding theory (SOGET), this novel extension of density-functional theory for model Hamiltonians shares many features with dynamical mean-field theory (DMFT) but is formally exact (in any dimension). In SOGET, the impurity-interacting correlation potential becomes a density-functional self-energy which is frequency-dependent and in principle non-local. A simple local density-functional approximation (LDA) combining the Bethe Ansatz (BA) LDA with the self-energy of the two-level Anderson model is constructed and successfully applied to the one-dimensional Hubbard model. Unlike in previous implementations of SOET, no many-body wavefunction is needed, thus reducing drastically the computational cost of the method.

Domaines: Physique [physics]; Matière Condensée [cond-mat]; Electrons fortement corrélés [cond-mat.str-el]

Laurent Mazouin, M. Saubanère, Emmanuel Fromager. Site-occupation Green's function embedding theory: A density functional approach to dynamical impurity solvers. Physical Review B, 2019, 100 (19), ⟨10.1103/PhysRevB.100.195104⟩. ⟨hal-02346416⟩