Strong Electronic Correlations: Dynamical Mean-Field Theory and Beyond

Hafermann, Hartmut; Lechermann, Frank; Rubtsov, A. N.; Katsnelson, M. I.; Georges, Antoine; Lichtenstein, A. I.

doi:10.1007/978-3-642-10449-7_4

Cited by 4 publications

(3 citation statements)

References 105 publications

(153 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Method. We study the model in the ladder dual fermion approximation [35][36][37][38][39][40] using the open source code of Ref. [41].…”

mentioning

confidence: 99%

Magnetic and charge susceptibilities in the half-filled triangular lattice Hubbard model

Gull

2020

Phys. Rev. Research

View full text Add to dashboard Cite

We study magnetic and charge susceptibilities in the half-filled two-dimensional triangular Hubbard model within the dual fermion approximation in the metallic, Mott insulating, and crossover regions of parameter space. In the insulating state, we find strong spin fluctuations at the K point at low energy corresponding to the 120 • antiferromagnetic order. These spin fluctuations persist into the metallic phase and move to higher energy. We also present data for simulated neutron spectroscopy and spin-lattice relaxation times, and perform direct comparisons to inelastic neutron spectroscopy experiments on the triangular material Ba8CoNb6O24 and to the relaxation times on κ-(ET)2Cu2(CN)3. Finally, we present charge susceptibilities in different areas of parameter space, which should correspond to momentum-resolved electron-loss spectroscopy measurements on triangular compounds., suggests that these compounds are close to a two-dimensional triangular structure and exhibit interesting electron correlation behavior including, potentially, a quantum spin liquid phase [7] in the ground state [8]. These compounds, as well as the low energy physics of the fully isotropic triangular material Ba 8 CoNb 6 O 24 [9], may be described by a half-filled single orbital Hubbard model on a triangular two-dimensional lattice, with an on-site Coulomb interaction strength comparable to or larger than the bandwidth [10].Because of the subtle competition of metallic, ordered, and spin liquid phases in the ground state, this model has been studied extensively with a wide range of numerical tools, including exact diagonalization (ED) [11][12][13], density matrix renormalization group theory (DMRG) [8], variational Monte Carlo (VMC) [14][15][16][17], variational cluster approximation [18][19][20], strong coupling expansions [21], path integral renormalization group techniques [22], and cluster dynamical mean field theory (DMFT) in the cellular [23][24][25][26][27] and dynamical cluster [28,29] variants. The focus in most of these studies has been on the precise location of the phase boundaries, ordering (or the absence thereof), and on the nature of these phases.Experimentally, much of our knowledge about correlated triangular systems is obtained from single-and two-particle scattering experiments such as photoemission [30], Raman spectroscopy [31], nuclear magnetic resonance (NMR) [2,32], or inelastic neutron scattering [9,33]. To understand these experimental results, it is necessary to calculate the corresponding response functions as a function of energy and momentum. For neutron spectroscopy and angular-resolved photoemission spectroscopy, in particular, both fine momentum and energy resolutions are desired. Such results are difficult to obtain, as computational methods formulated on finite lattices (such as ED, DMRG, and cluster DMFT) pro-

show abstract

“…Method. We study the model in the ladder dual fermion approximation [35][36][37][38][39][40] using the open source code of Ref. [41].…”

mentioning

confidence: 99%

Magnetic and charge susceptibilities in the half-filled triangular lattice Hubbard model

Gull

2020

Phys. Rev. Research

View full text Add to dashboard Cite

show abstract

“…Instead, the presence of dynamical AFM correlations decreases the fluctuations and leads to an interplay of Slater and Mott physics that increases the coherence of the single-particle excitations. A similar situation occurs in the two-dimensional square lattice [31].…”

Section: Dual-fermion Methodsmentioning

confidence: 54%

From Hubbard bands to spin-polaron excitations in the doped Mott materialNaxCoO2

et al. 2015

Self Cite

View full text Add to dashboard Cite

We investigate the excitation spectrum of strongly correlated sodium cobaltate within a realistic many-body description beyond dynamical mean-field theory (DMFT). At lower doping around x = 0.3, rather close to Mott-critical half-filling, the single-particle spectral function of Na x CoO 2 displays an upper Hubbard band which is captured within DMFT. Momentum-dependent self-energy effects beyond DMFT become dominant at higher doping. Around a doping level of x ∼ 0.67, the incoherent excitations give way to finite-energy spin-polaron excitations in close agreement with optics experiments. These excitations are a direct consequence of the formation of bound states between quasiparticles and paramagnons in the proximity of in-plane ferromagnetic ordering.

show abstract

“…Some times we will omit all orbital indices for simplicity. All equations will be written in matrix form, giving the idea of how to generalize a DF scheme to the multiorbital case [17,18]. The general strategy to separate the local and non-local correlations effects is associated with the introduction of auxiliary fermionic ¿elds which will couple separated local correlated impurities models back to the lattice [16].…”

Section: Local Correlations and Beyondmentioning

confidence: 99%

Correlation effects in solids: From DFT to DMFT

Lichtenstein

2013

AIP Conference Proceedings

View full text Add to dashboard Cite

Abstract. In this lecture we give an introduction to theoretical description of strongly correlated materials based on dynamical mean-¿eld theory (DMFT) and its extensions. The goal of this theoretical construction is to retain the many-body aspects of local atomic physics within the extended solid. The effects of short-range non-local correlations within cluster extensions of the DMFT scheme, as well as long-range Àuctuations within the fully renormalized dual-fermion perturbation scheme are discussed extensively. Recent progress in the numerical solution of the DMFT effective quantum impurity problem within the recently developed continuous-time Quantum Monte Carlo schemes is reviewed. We then describe realistic extensions of this approach which combine the accuracy of ¿rst-principle Density-Functional Theory with the treatment of local many-body effects within DMFT.

show abstract

Strong Electronic Correlations: Dynamical Mean-Field Theory and Beyond

Cited by 4 publications

References 105 publications

Magnetic and charge susceptibilities in the half-filled triangular lattice Hubbard model

Magnetic and charge susceptibilities in the half-filled triangular lattice Hubbard model

From Hubbard bands to spin-polaron excitations in the doped Mott materialNaxCoO2

Correlation effects in solids: From DFT to DMFT

Contact Info

Product

Resources

About