Thermodynamics of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>α</mml:mi></mml:math>-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>γ</mml:mi></mml:math>transition in cerium from first principles

Bieder, Jordan; Amadon, Bernard

doi:10.1103/physrevb.89.195132

Cited by 52 publications

(62 citation statements)

References 45 publications

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“…This is consistent with results of Lanata et al [47] finding very similar zero slope of −dE/dV at zero temperature, but is inconsistent with Ref. 27, which finds no feature in total energy. It is also inconsistent with McMahan et.al [11] showing clear double-peak in total energy.…”

supporting

confidence: 35%

“…On the basis of LDA+DMFT calculation McMahan et.al [11] proposed that the total energy exhibits a double-minimum shape, concomitant with the appearance of the quasiparticle peak at temperature as high as 1500 K, signaling the first order transition. Using different implementation of the same method, Amadon et.al [27,46] proposed that the transition is entropy driven, and that the total energy is featureless with the minimum corresponding to low volume α-phase. Only the addition of the entropy term moves the minimum to the larger volume of γ-phase.…”

mentioning

confidence: 99%

“…4 are relatively straightforward to evaluate, however, for a high precision implementation one needs to combine the terms that largely cancel and evaluate them together [4]. Previous implementations of free energy within LDA+DMFT [25,27,36] were based on i) evaluating the total energy Eq. 1 at range of temperatures, and integrating resulting specific heat [36], and ii) the coupling constant integration [25,27], where total energy of the solid is needed for a range of coulomb repulsion's U and is than integrated over U .…”

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confidence: 99%

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Free Energy from Stationary Implementation of theDFT+DMFTFunctional

2015

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The stationary functional of the all-electron density functional plus dynamical mean field theory (DFT+DMFT) formalism to perform free energy calculations and structural relaxations is implemented for the first time. Here, the first order error in the density leads to a much smaller, second order error in the free energy. The method is applied to several well known correlated materials; metallic SrVO3, Mott insulating FeO, and elemental Cerium, to show that it predicts the lattice constants with very high accuracy. In Cerium, we show that our method predicts the iso-structural transition between the α and γ phases, and resolve the long standing controversy in the driving mechanism of this transiton. PACS numbers: 71.27.+a,71.30.+h Prediction of the crystal structures of solids by large scale quantum mechanical simulations is one of the fundamental problems of condensed matter physics, and occupies a central place in materials design. The workhorse of the field is the Density Functional Theory (DFT) [1] at the level of Local Density Approximation (LDA) or Generalized Gradient Approximations (GGAs), which predict lattice constants of weakly correlated materials typically within ∼1% relative error [2].These errors of DFT in LDA/GGA implementations are an order of magnitude larger in the so called correlated materials: For example, the lattice constant of δ-Pu is underestimated by 11% [3] or non-magnetic FeO by 7% [4]. While GGAs and hybrid functionals can sometimes improve upon conventional LDA, these functionals many times degrade the agreement between predicted and experimentally determined bulk moduli and lattice constants, in particular in materials containing heavy elements. [2] To account for the correlation effects, more sophisticated many body methods have been developed. Among them, one of the most successful algorithms is the dynamical mean-field theory (DMFT) [5]. It replaces the problem of describing correlation effects in a periodic lattice by a strongly interacting impurity coupled to a self-consistent bath [6]. To become material specific, DMFT was soon developed into an electronic structure tool (LDA+DMFT) [7, 8], which achieved great success in numerous correlated materials (for a review see [9]). The LDA+DMFT method has mainly been used for the calculation of spectroscopic quantities, and only a few dozens of studies managed to compute energetics of correlated solids, and only a handful of them used exact solvers and charge self-consistency [18,19,24,25,28,29]. This is not only because of the very high computational cost, but also because previous implementations of LDA+DMFT were not stationary, and hence it was hard to achieve precision of free energies needed for structure optimization and study of phase transitions in solids.Here we implemented the LDA+DMFT functional, which delivers stationary free energies at finite temperatures. This stationarity is crucial for practical implementation and precision of computed energies, since the first order error in the density ρ (or the Green's fu...

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Free Energy from Stationary Implementation of theDFT+DMFTFunctional

2015

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“…Since the GA ground-state properties are generally in very good agreement with DMFT for strongly correlated metals [23,27,35,65,66]-even though the GA is much less computationally demanding-this observation opens up the possibility to use the GA for structural relaxation and to determine V dc i and ρðrÞ, and to perform a single DMFT iteration afterwards, in order to also have access to the spectral properties of the system of interest.…”

Section: Charge Self-consistency and Ksh Hamiltonianmentioning

confidence: 99%

Phase Diagram and Electronic Structure of Praseodymium and Plutonium

Lanatà¹,

Yao²,

et al. 2015

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We develop a new implementation of the Gutzwiller approximation in combination with the local density approximation, which enables us to study complex 4f and 5f systems beyond the reach of previous approaches. We calculate from first principles the zero-temperature phase diagram and electronic structure of Pr and Pu, finding good agreement with the experiments. Our study of Pr indicates that its pressure-induced volume-collapse transition would not occur without change of lattice structure-contrarily to Ce. Our study of Pu shows that the most important effect originating the differentiation between the equilibrium densities of its allotropes is the competition between the Peierls effect and the Madelung interaction and not the dependence of the electron correlations on the lattice structure.

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“…Fully charge selfconsistent calculations using approximate DMFT impurity solvers also have been performed to study the elastic properties of Ce [10], Ce 2 O 3 [10,11], and Pu 2 O 3 [10]. Very recently, fully charge self-consistent calculations which use continuous-time QMC to solve the DMFT impurity problem have been used to calculate the z position of the As atom in iron pnictides [12,13] and the thermodynamics of V 2 O 3 [14], Ce [15]. These most advanced studies have not yet addressed a phase transition between two different structures.…”

Section: Introductionmentioning

confidence: 99%

Total energy calculations using DFT+DMFT: Computing the pressure phase diagram of the rare earth nickelates

2014

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A full implementation of the ab initio density functional plus dynamical mean field theory (DFT+DMFT) formalism to perform total energy calculations and structural relaxations is proposed and implemented. The method is applied to the structural and metal-insulator transitions of the rare earth nickelate perovskites as a function of rare earth ion, pressure, and temperature. In contrast to previous DFT and DFT+U theories, the present method accounts for the experimentally observed structure of LaNiO3 and the insulating nature of the other perovskites, and quantitatively reproduces the metal-insulator and structural phase diagram in the plane of pressure and rare earth element. The temperature dependence of the energetics of the phase transformation indicates that the thermal transition is driven by phonon entropy effects.

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Thermodynamics of theα-γtransition in cerium from first principles

Cited by 52 publications

References 45 publications

Free Energy from Stationary Implementation of theDFT+DMFTFunctional

Free Energy from Stationary Implementation of theDFT+DMFTFunctional

Phase Diagram and Electronic Structure of Praseodymium and Plutonium

Total energy calculations using DFT+DMFT: Computing the pressure phase diagram of the rare earth nickelates

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