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Journal Articles Physical Review B: Condensed Matter and Materials Physics (1998-2015) Year : 2015

Mott physics and spin fluctuations: a unified framework

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Abstract

We 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.

Dates and versions

cea-01232442 , version 1 (23-11-2015)

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Thomas Ayral, Olivier Parcollet. Mott physics and spin fluctuations: a unified framework. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2015, 92, pp.115109. ⟨10.1103/PhysRevB.92.115109⟩. ⟨cea-01232442⟩
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