Charge ordering and nonlocal correlations in the doped extended Hubbard model

Terletska, Hanna; Chen, Tianran; Paki, Joseph; Gull, Emanuel

doi:10.1103/physrevb.97.115117

Cited by 25 publications

(30 citation statements)

References 90 publications

(96 reference statements)

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“…As explored in previous work 49,50 (see also results from other methods 34,46,[77][78][79] ), the CO transition occurs above the mean field line 80 , has a non-zero intercept at U = 0, and is only weakly temperature dependent. In contrast, the AFM phase in this approximation is very strongly temperature dependent for these parameters, hinting at a rapid evolution of the spin susceptibility in this model, and moves to substantially lower U and larger V as the temperature is lowered (compare to the right panel).…”

Section: B V -U Phase Diagramsupporting

confidence: 56%

“…Solving the cluster impurity problem requires the use of a quantum impurity solver. Here we use the continuous time auxiliary field quantum Monte Carlo algorithm (CTAUX) [74][75][76] , modified to accommodate nonlocal density-density interactions 49,50 .…”

Section: Model and Methodsmentioning

confidence: 99%

“…30 The interplay between inter-cite interaction V , local interaction U , temperature, and doping effects thereby generates the rich phase diagram of the model. The extended Hubbard model has been of interest both as a proxy for the exploration of charge order caused by electron repulsion 24,25,27,29,[31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] and as a model system for testing the effect of non-local interactions on electron correlations. [51][52][53][54][55] In that context, it has been particularly valuable to illustrate the convergence of diagrammatic extensions of the dynamical mean field theory 56,57 (DMFT) including the GW+DMFT 34,35,58 and the dual boson approximation.…”

Section: Introductionmentioning

confidence: 99%

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Charge order and antiferromagnetism in the extended Hubbard model

et al. 2019

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We study the extended Hubbard model on a two-dimensional half-filled square lattice using the dynamical cluster approximation. We present results on the phase boundaries between the paramagnetic metallic (normal) state and the insulating antiferromagnetic state, as well as between the antiferromagnetic and charge order states. We find hysteresis along the antiferromagnet/charge order and normal/charge order phase boundaries (at larger values of the on-site interaction), indicating first order phase transitions. We show that nearest neighbor interactions lower the critical temperature for the antiferromagnetic phase. We also present results for the effect of nearest neighbor interactions on the antiferromagnetic phase boundary and for the evolution of spectral functions and energetics across the phase transitions. arXiv:1904.02249v1 [cond-mat.str-el]

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Section: B V -U Phase Diagramsupporting

confidence: 56%

Section: Model and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Charge order and antiferromagnetism in the extended Hubbard model

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“…The effects of Coulomb's interactions between electrons located on neighboring lattice sites have already been intensively investigated for the extended Hubbard model, e.g., Refs. [35][36][37][38][39][40][41][42][43][44] and references therein, while for the EFKM only very few results have been reported so far [34,[45][46][47][48][49]. As far as we know, exact results for the EFKM were only reported in Refs.…”

Section: Introductionmentioning

confidence: 99%

Extended Falicov-Kimball model: Exact solution for finite temperatures

2019

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The extended Falicov-Kimball model is analyzed exactly for finite temperatures in the limit of large dimensions. The onsite, as well as the intersite density-density interactions represented by the coupling constants U and V , respectively, are included in the model. Using the dynamical mean field theory formalism on the Bethe lattice we find rigorously the temperature dependent density of states (DOS) at half-filling. At zero temperature (T = 0) the system is ordered to form the checkerboard pattern and the DOS has the gap ∆(εF ) > 0 at the Fermi level, if only U = 0 or V = 0. With an increase of T the DOS evolves in various ways that depend both on U and V . If U < 0 or U > 2V , two additional subbands develop inside the principal energy gap. They become wider with increasing T and at a certain U -and V -dependent temperature TMI they join with each other at εF . Since above TMI the DOS is positive at εF , we interpret TMI as the transformation temperature from insulator to metal. It appears, that TMI approaches the order-disorder phase transition temperature TOD for |U | = 2 and 0 < U 2V , but otherwise TMI is substantially lower than TOD. Moreover, we show that if V 0.54 then TMI = 0 at two quasi-quantum critical points U ± cr (one positive and the other negative), whereas for V 0.54 there is only one negative U − cr . Having calculated the temperature dependent DOS we study thermodynamic properties of the system starting from its free energy F and then we construct the phase diagrams in the variables T and U for a few values of V . Our calculations give that inclusion of the intersite coupling V causes the finite temperature phase diagrams to become asymmetric with respect to a change of sign of U . On these phase diagrams we detected stability regions of eight different kinds of ordered phases, where both charge-order and antiferromagnetism coexists (five of them are insulating and three are conducting) and three different nonordered phases (two of them are insulating and one is conducting). Moreover, both continuous and discontinuous transitions between various phases were found. PACS numbers: 71.30.+h Metal-insulator transitions and other electronic transitions; 71.10.Fd Lattice fermion models (Hubbard model, etc.); 71.27.+a Strongly correlated electron systems; heavy fermions; 71.10.-w Theories and models of many-electron systems.model (FKM) [16,[20][21][22][23][24][25][26][27][28][29][30], sometimes referred to as the simplified Hubbard model. Recently, the FKM has been also investigated by a cluster extension of the DMFT [31][32][33]. The simplest version of the FKM describes spinless electrons interacting with localized ions via only the local (on-site) Coulomb coupling U .So far, the FKM has been used to describe various effects, such as crystal formation, mixed valence, metalinsulator phase transition, and so on, e.g., Refs. [2,15,16,20]. In particular, in Refs. [29,30] there were analyzed exactly properties of this model (in D → ∞) related to the order-disorder phase transition caused by a rise of ...

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“…In contrast to the Hubbard model, the properties of the extended Hubbard model are far less well understood. It is known that strong non-local interactions can induce charge density waves [14][15][16][17][18], influence superconducting properties [19][20][21][22], screen local correlations [23][24][25] lead to band-widening effects [26,27], first-order metal-insulator transitions [28], and renormalization of Fermi velocities [29,30]. However, systematic studies of thermodynamic properties are rare and reference data for detailed comparisons and benchmarks between methods especially in context of the metal-insulator transition is missing.Here, we systematically study the half-filled square lattice in the thermodynamic limit (Sec.…”

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confidence: 99%

Thermodynamics of the metal-insulator transition in the extended Hubbard model

et al. 2019

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In contrast to the Hubbard model, the extended Hubbard model, which additionally accounts for non-local interactions, lacks systemic studies of thermodynamic properties especially across the metal-insulator transition. Using a variational principle, we perform such a systematic study and describe how non-local interactions screen local correlations differently in the Fermi-liquid and in the insulator. The thermodynamics reveal that non-local interactions are at least in parts responsible for first-order metal-insulator transitions in real materials. Contents 1 arXiv:1903.09947v3 [cond-mat.str-el]The Hubbard model [1][2][3][4][5] of itinerant electrons with a local interaction is arguably the simplest model describing the competition between kinetic energy and interaction. It is of enormous importance for the understanding of strongly correlated materials and it is thus not surprising that much effort has been spent on unveiling its properties through analytical, numerical, and experimental methods. Since the advent of experiments on cold atoms, which closely simulate the Hubbard model, simulations can even be benchmarked against actual experimental data [6] for high temperatures.Energetics and entropy are, for instance, well known for a broad parameter regime from cold atom experiments [7,8] and complementary numerical simulations using the numerical linked cluster expansion (NLCE) [9], dynamical cluster approximation (DCA) [10], determinant quantum Monte Carlo (DQMC) [11], and recently variational cluster approximation (VCA) [12] and cellular dynamical mean field theory [13].Despite its usefulness for understanding the principles of strongly correlated electron physics, the Hubbard model is quite far from describing real materials: Electrons in real materials interact by long-range Coulomb interaction which in the Hubbard model is approximated by neglecting all but on-site interactions.A more realistic model Hamiltonian in that sense is the extended Hubbard model that incorporates interactions between electrons on different lattice sites. In contrast to the Hubbard model, the properties of the extended Hubbard model are far less well understood. It is known that strong non-local interactions can induce charge density waves [14][15][16][17][18], influence superconducting properties [19][20][21][22], screen local correlations [23][24][25] lead to band-widening effects [26,27], first-order metal-insulator transitions [28], and renormalization of Fermi velocities [29,30]. However, systematic studies of thermodynamic properties are rare and reference data for detailed comparisons and benchmarks between methods especially in context of the metal-insulator transition is missing.Here, we systematically study the half-filled square lattice in the thermodynamic limit (Sec. 3). The study includes the transition from Fermi-liquid to insulator in the Slater regime (compare Fig. 1a). We describe two distinct mechanisms of how non-local interactions suppress correlation effects: First, in the Fermi-liquid by effectively reduci...

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Charge ordering and nonlocal correlations in the doped extended Hubbard model

Cited by 25 publications

References 90 publications

Charge order and antiferromagnetism in the extended Hubbard model

Charge order and antiferromagnetism in the extended Hubbard model

Extended Falicov-Kimball model: Exact solution for finite temperatures

Thermodynamics of the metal-insulator transition in the extended Hubbard model

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