Quasi-particle energy spectra in local reduced density matrix functional theory

Lathiotakis, N. N.; Helbig, Nicole; Rubio, Ángel; Gidopoulos, Nikitas I.

doi:10.1063/1.4899072

Cited by 16 publications

(20 citation statements)

References 67 publications

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“…The relative differences for all functionals lie in the range of 32%-463%. This is largely expected since local-RDMFT energy eigenvalues have been proven to give accurate approximations to the experimental IPs 24,25 contrary to the LDA ones. The big difference from the LDA eigenvalues can be partly attributed to constraints (3) and (4).…”

Section: Resultsmentioning

confidence: 99%

“…Apart from reducing the numerical cost, the local-RDMFT framework provides an energy eigenvalue spectrum connected to the LROs. We found that the energy eigenvalues of the strongly occupied orbitals reproduce the ionization potentials of small and large molecules 24,25 accurately. We now turn our attention to the question of how the LROs compare with different sets of orbitals like the almost exact NOs taken from MCSCF calculations, those from the full RDMFT minimization, and the KS orbitals of LDA.…”

Section: Local Rdmftmentioning

confidence: 92%

“…It was found that those energy eigenvalues are very good approximations for the ionization potentials (IPs) of a set of atomic and molecular systems 24,25 although a mathematical proof of their association with the IPs is lacking. In the present work, we refer to RDMFT with the full minimization of the NOs as full-RDMFT and use the prefix full also for specific functionals, e.g., full-Müller, in order to distinguish from local-RDMFT for which the prefix local will be used.…”

Section: Introductionmentioning

confidence: 99%

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Orbitals from local RDMFT: Are they Kohn-Sham or natural orbitals?

Θεοφίλου

Lathiotakis

Gidopoulos

et al. 2015

The Journal of Chemical Physics

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Recently, an approximate theoretical framework was introduced, called local reduced density matrix functional theory (local-RDMFT), where functionals of the one-body reduced density matrix (1-RDM) are minimized under the additional condition that the optimal orbitals satisfy a single electron Schrödinger equation with a local potential. In the present work, we focus on the character of these optimal orbitals. In particular, we compare orbitals obtained by local-RDMFT with those obtained with the full minimization (without the extra condition) by contrasting them against the exact NOs and orbitals from a density functional calculation using the local density approximation (LDA). We find that the orbitals from local-RMDFT are very close to LDA orbitals, contrary to those of the full minimization that resemble the exact NOs. Since local RDMFT preserves the good quality of the description of strong static correlation, this finding opens the way to a mixed density/density matrix scheme, where Kohn-Sham orbitals obtain fractional occupations from a minimization of the occupation numbers using 1-RDM functionals. This will allow for a description of strong correlation at a cost only minimally higher than a density functional calculation. C 2015 AIP Publishing LLC.[http://dx

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Section: Resultsmentioning

confidence: 99%

Section: Local Rdmftmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Orbitals from local RDMFT: Are they Kohn-Sham or natural orbitals?

Θεοφίλου

Lathiotakis

Gidopoulos

et al. 2015

The Journal of Chemical Physics

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“…In practice, however, the correlation energy is an unknown functional of the 1-RDM and must be approximated. Although there are several known approximations for the xc energy functional [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34], the most promising for extended systems is the power functional [14,15] where the xc energy reads…”

Section: Introductionmentioning

confidence: 99%

Spectrum for Nonmagnetic Mott Insulators from Power Functional within Reduced Density Matrix Functional Theory

Shinohara

Sharma

Shallcross

et al. 2015

J. Chem. Theory Comput.

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A fully first principles theory capable of treating strongly correlated solids remains the outstanding challenge of modern day materials science. This is exemplified by the transition metal oxides, prototypical Mott insulators, that remain insulating even in the absence of long range magnetic order. Capturing the non-magnetic insulating state of these materials presents a difficult challenge for any modern electronic structure theory. In this paper we demonstrate that reduced density matrix functional theory, in conjunction with the power functional, can successfully treat the nonmagnetic insulating state of the transition metal oxides NiO and MnO. We show that the electronic spectrum retains a gap even in the absence of spin order. We further discuss the detailed way in which RDMFT performs for Mott insulators and band insulators, finding that for the latter occupation number minimization alone is required, but for the former full minimization over both occupation numbers and natural orbitals is essential.

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“…Properties like spectra or static response functions, like static dipole polarizabilities [102], however are not directly accessible. Several methods have been proposed to estimate photoemission spectra starting from Slater's transition state [70,103], local RDMFT [104,105] and approximations in terms of higher order RDMs [69]. Applications of these approaches to models systems [18,69] as well as real materials [69][70][71] showed mixed performances.…”

Section: Gaps and Spectral Informationmentioning

confidence: 99%

Reduced density-matrix functionals from many-particle theory

Schade

Kamil

Blöchl

2017

Eur. Phys. J. Spec. Top.

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Abstract. In materials with strong electron correlation the proper treatment of local atomic physics described by orbital occupations is crucial. Reduced density-matrix functional theory is a natural extension of density functional theory for systems that are dominated by orbital physics. We review the current state of reduced density-matrix functional theory (RDMFT). For atomic structure relaxations or abinitio molecular dynamics the combination of density functional theory (DFT) and dynamical mean-field theory (DMFT) possesses a number of disadvantages, like the cumbersome evaluation of forces. We therefore describe a method, DFT+RDMFT, that combines many-particle effects based on reduced density-matrix functional theory with a density functional-like framework. A recent development is the construction of density-matrix functionals directly from many-particle theory such as methods from quantum chemistry or many-particle Green's functions. We present the underlying exact theorems and describe current progress towards quantitative functionals.

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Quasi-particle energy spectra in local reduced density matrix functional theory

Cited by 16 publications

References 67 publications

Orbitals from local RDMFT: Are they Kohn-Sham or natural orbitals?

Orbitals from local RDMFT: Are they Kohn-Sham or natural orbitals?

Spectrum for Nonmagnetic Mott Insulators from Power Functional within Reduced Density Matrix Functional Theory

Reduced density-matrix functionals from many-particle theory

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