Generalized dynamical mean-field theory in physics of strongly correlated systems

TL;DR

This review discusses an advanced extension of dynamical mean-field theory (DMFT), called DMFT+Sigma, which incorporates additional interactions to better describe phenomena in strongly correlated electronic systems, including pseudogap formation and metal-insulator transitions.

Contribution

It introduces the DMFT+Sigma approach that accounts for various interactions within DMFT, and extends it to realistic materials via LDA+DMFT, enabling detailed modeling of complex phenomena in strongly correlated systems.

Findings

Modeling of pseudogap state in high-Tc cuprates consistent with ARPES data

Description of metal-insulator transition in disordered systems

Analysis of kink formation in electronic spectra

Abstract

This review is devoted to generalization of dynamical mean-field theory (DMFT) for strongly correlated electronic systems towards the account of different types of additional interactions, necessary for correct physical description of many experimentally observed phenomena in such systems. As additional interactions we consider: (1) interaction of electrons with antiferromagnetic (or charge) fluctuations of order parameter in high-Tc superconductors leading to the formation of pseudogap state, (2) scattering of electrons on static disorder and its role in general picture of Anderson-Hubbard metal-insulator transition, (3) electron-phonon interaction and corresponding anomalies of electronic spectra in strongly correlated systems. Proposed DMFT+Sigma approach is based on taking into account above mentioned interactions by introducing additional self-energy Sigma (in general momentum dependent) into conventional DMFT scheme and calculated in a self-consistent way within the standard set of DMFT equations. Here we formulate general scheme of calculation of both one-particle (spectral functions and densities of states) and two-particle (optical conductivity) properties. We examine the problem of pseudogap formation, including the Fermi arc formation and partial destruction of the Fermi surface, metal-insulator transition in disordered Anderson-Hubbard model, and general picture of kink formation within electronic spectra in strongly correlated systems. DMFT+Sigma approach is generalized to describe realistic materials with strong electron-electron correlations based on LDA+DMFT method. General scheme of LDA+DMFT method is presented together with some of its applications to real systems. The LDA+DMFT+Sigma approach is employed to modelling of pseudogap state of electron and hole doped high-T_c cuprates. Comparison with variety of ARPES experiments is given.