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McMahan, A. K.; Huscroft, Carey; Scalettar, R. T.; Pollock, E. L.

doi:10.1023/a:1008698422183

Cited by 107 publications

(106 citation statements)

References 70 publications

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“…The calculation of the specific heat is a notoriously difficult problem and usually involves a fit of E(T) to a regularized (smooth) functional form. 16,17 Here, we already have an excellent fit, so we ob tain C / T from a derivative of the fit divided by temperature. The result is shown in the inset.…”

Section: Resultsmentioning

confidence: 99%

Thermodynamics of the quantum critical point at finite doping in the two-dimensional Hubbard model studied via the dynamical cluster approximation

et al. 2009

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We study the thermodynamics of the two-dimensional Hubbard model within the dynamical cluster approxi mation. We use continuous time quantum Monte Carlo as a cluster solver to avoid the systematic error which complicates the calculation of the entropy and potential energy (double occupancy). We find that at a critical filling, there is a pronounced peak in the entropy divided by temperature, S / T, and in the normalized double occupancy as a function of doping. At this filling, we find that specific heat divided by temperature, C / T, increases strongly with decreasing temperature and kinetic and potential energies vary like T 2 ln T. These are all characteristics of quantum critical behavior.

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Section: Resultsmentioning

confidence: 99%

Thermodynamics of the quantum critical point at finite doping in the two-dimensional Hubbard model studied via the dynamical cluster approximation

et al. 2009

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“…It shows an unique isostructural (fcc to fcc) α → γ phase transition with increasing temperature. The high-temperature γ phase has 15% larger volume and displays a Curie-Weiss-like temperature dependence of the magnetic susceptibility signaling the existence of local magnetic moments while the α-phase has a Pauli-like temperature independent paramagnetism [1].While many different models were proposed to describe this system (for a review see [2]), the most relevant seems to be the periodic Anderson model. Studies based on the single impurity Anderson model [3] with a hybridization function obtained from LDA band structure calculations were rather successful in reproducing Kondo scales and spectra for α-and γ-Ce.…”

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confidence: 99%

Spectral and Magnetic Properties ofα- andγ-Ce from Dynamical Mean-Field Theory and Local Density Approximation

et al. 2001

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We have calculated ground state properties and excitation spectra for Ce metal with the ab initio computational scheme combining local density approximation and dynamical mean-field theory (LDA+DMFT). We considered all electronic states, i.e. correlated f -states and non-correlated s-, p-and d-states. The strong local correlations (Coulomb interaction) among the f -states lead to typical many-body resonances in the partial f -density, such as lower and upper Hubbard band. Additionally the well known Kondo resonance is observed. The s-, p-and d-densities show small to mediate renormalization effects due to hybridization. We observe different Kondo temperatures for α-and γ-Ce (TK,α ≈ 1000 K and TK,γ ≈ 30 K), due to strong volume dependence of the effective hybridization strength for the localized f -electrons. Finally we compare our results with a variety of experimental data, i.e. from photoemission spectroscopy (PES), inverse photoemission spectroscopy (BIS), resonant inverse photoemission spectroscopy (RIPES) and magnetic susceptibility measurements.71.27.+a Strongly correlated electron systems , 74.25.Jb Electronic structure Ce metal is the simplest lanthanide compound with only one atom in a face centered cubic (fcc) crystal structure and a relatively small set of relevant electronic states derived from s-, p-d-and f -orbitals of Ce. It shows an unique isostructural (fcc to fcc) α → γ phase transition with increasing temperature. The high-temperature γ phase has 15% larger volume and displays a Curie-Weiss-like temperature dependence of the magnetic susceptibility signaling the existence of local magnetic moments while the α-phase has a Pauli-like temperature independent paramagnetism [1].While many different models were proposed to describe this system (for a review see [2]), the most relevant seems to be the periodic Anderson model. Studies based on the single impurity Anderson model [3] with a hybridization function obtained from LDA band structure calculations were rather successful in reproducing Kondo scales and spectra for α-and γ-Ce. However, an empirical renormalization of the hybridization function and position of the impurity level were needed for satisfactory agreement between calculated and experimental spectra.Due to the recent development of the Dynamical Mean-Field Theory [4] a more realistic treatment of Ce is now possible. In contrast to the Hubbard model (degenerate and non-degenerate), where hybridization occurs only between correlated d-or f -orbitals, Ce is much more complicated. The direct f -f hybridization is of the same order of magnitude as the hybridization of f -orbitals with the delocalized spd-states. Thus in order to describe Ce one even has to go beyond the periodic Anderson model, where only hybridization of the correlated f -orbitals with the delocalized states is included. In order to address this problem we used the most general procedure for calculating the Green function using a full basis set (s, p, d, f ) Hamiltonian with the integration over Brillouin zone in k-space....

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“…The mean-field solution corresponding to the paramagnetic metal at T = 0 disappears at a critical coupling U c2 . At this point, the quasiparticle weight vanishes (Z ∝ 1 −U /U c2 ) as in Brinkman-Rice theory 15 On the other hand, a mean-field insulating solution is found for U > U c1 , with the Mott gap ∆ opening up at this critical coupling (Mott-Hubbard transition). As a result, ∆ is a finite energy scale for U = U c2 and the quasiparticle peak in the d.o.s is well separated from the Hubbard bands in the strongly correlated metal.…”

Section: Separation Of Energy Scales Spinodals and Transition Linementioning

confidence: 80%

“…The unit-cell volume has a very characteristic, roughly parabolic, dependence. A simple model of a narrow band being gradually filled, introduced long ago by Friedel [14] accounts for this parabolic dependence (see also [15,16]). Because the states at the bottom of the band are bonding-like while the states at the top of the band are anti-bonding like, the binding energy is maximal (and hence the equilibrium volume is minimal) for a half-filled shell.…”

Section: Transition Metalsmentioning

confidence: 99%

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Strongly Correlated Electron Materials: Dynamical Mean-Field Theory and Electronic Structure

Georges¹

2004

AIP Conference Proceedings

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Abstract. These are introductory lectures to some aspects of the physics of strongly correlated electron systems. I first explain the main reasons for strong correlations in several classes of materials. The basic principles of dynamical mean-field theory (DMFT) are then briefly reviewed. I emphasize the formal analogies with classical mean-field theory and density functional theory, through the construction of free-energy functionals of a local observable. I review the application of DMFT to the Mott transition, and compare to recent spectroscopy and transport experiments. The key role of the quasiparticle coherence scale, and of transfers of spectral weight between low-and intermediate or high energies is emphasized. Above this scale, correlated metals enter an incoherent regime with unusual transport properties. The recent combinations of DMFT with electronic structure methods are also discussed, and illustrated by some applications to transition metal oxides and f-electron materials.

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Untitled

Cited by 107 publications

References 70 publications

Thermodynamics of the quantum critical point at finite doping in the two-dimensional Hubbard model studied via the dynamical cluster approximation

Thermodynamics of the quantum critical point at finite doping in the two-dimensional Hubbard model studied via the dynamical cluster approximation

Spectral and Magnetic Properties ofα- andγ-Ce from Dynamical Mean-Field Theory and Local Density Approximation

Strongly Correlated Electron Materials: Dynamical Mean-Field Theory and Electronic Structure

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