https://hal-cea.archives-ouvertes.fr/cea-01232442Ayral, ThomasThomasAyralIPHT - Institut de Physique Théorique - UMR CNRS 3681 - CEA - Commissariat à l'énergie atomique et aux énergies alternatives - Université Paris-Saclay - CNRS - Centre National de la Recherche ScientifiqueParcollet, OlivierOlivierParcolletSPhT - Service de Physique Théorique - CEA - Commissariat à l'énergie atomique et aux énergies alternatives - CNRS - Centre National de la Recherche ScientifiqueMott physics and spin fluctuations: a unified frameworkHAL CCSD2015[PHYS] Physics [physics]De Laborderie, Emmanuelle2015-11-23 15:04:502023-02-09 04:46:522015-11-23 15:04:50enJournal articles10.1103/PhysRevB.92.1151091We present a formalism for strongly correlated electrons systems which consists in a local approximation of the dynamical three-leg interaction vertex. This vertex is self-consistently computed with a quantum impurity model with dynamical interactions in the charge and spin channels, similar to dynamical mean field theory (DMFT) approaches. The electronic self-energy and the polarization are both frequency and momentum dependent. The method interpolates between the spin-fluctuation or GW approximations at weak coupling and the atomic limit at strong coupling. We apply the formalism to the Hubbard model on a two-dimensional square lattice and show that as interactions are increased towards the Mott insulating state, the local vertex acquires a strong frequency dependence, driving the system to a Mott transition, while at low enough temperatures the momentum-dependence of the self-energy is enhanced due to large spin fluctuations. Upon doping, we find a Fermi arc in the one-particle spectral function, which is one signature of the pseudo-gap state.