Mott physics and spin fluctuations: a functional viewpoint - Archive ouverte HAL Access content directly
Journal Articles Physical Review B: Condensed Matter and Materials Physics (1998-2015) Year : 2016

Mott physics and spin fluctuations: a functional viewpoint

(1) , (1)
1

Abstract

We present a formalism for strongly correlated systems with fermions coupled to bosonic modes. We construct the three-particle irreducible functional $\mathcal{K}$ by successive Legendre transformations of the free energy of the system. We derive a closed set of equations for the fermionic and bosonic self-energies for a given $\mathcal{K}$. We then introduce a local approximation for $\mathcal{K}$, which extends the idea of dynamical mean field theory (DMFT) approaches from two- to three-particle irreducibility. This approximation entails the locality of the three-leg electron-boson vertex $\Lambda(i\omega,i\Omega)$, which is self-consistently computed using a quantum impurity model with dynamical charge and spin interactions. This local vertex is used to construct frequency- and momentum-dependent electronic self-energies and polarizations. By construction, the method interpolates between the spin-fluctuation or GW approximations at weak coupling and the atomic limit at strong coupling. We apply it to the Hubbard model on two-dimensional square and triangular lattices. We complement the results of Phys.Rev. B 92, 115109 by (i) showing that, at half-filling, as DMFT, the method describes the Fermi-liquid metallic state and the Mott insulator, separated by a first-order interacting-driven Mott transition at low temperatures, (ii) investigating the influence of frustration and (iii) discussing the influence of the bosonic decoupling channel.
Fichier principal
Vignette du fichier
1512.06719v2.pdf (1.11 Mo) Télécharger le fichier
Origin : Files produced by the author(s)

Dates and versions

cea-01341626 , version 1 (04-07-2016)

Identifiers

Cite

Thomas Ayral, Olivier Parcollet. Mott physics and spin fluctuations: a functional viewpoint. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2016, 93, pp.235124. ⟨10.1103/PhysRevB.93.235124⟩. ⟨cea-01341626⟩
57 View
96 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More