Benchmarking the <i>GW</i> Approximation and Bethe–Salpeter Equation for Groups IB and IIB Atoms and Monoxides

Hung, Linda; Bruneval, Fabien; Baishya, Kopinjol; Öğüt, Serdar

doi:10.1021/acs.jctc.7b00123

Cited by 40 publications

(46 citation statements)

References 75 publications

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“…Experimental details on sample preparation, X-ray diffraction and UV-vis spectroscopy measurements, computational details on QSGW and BSE calculations, and additional Ref. [37][38][39][40][41][42][43][44][45][46]…”

Section: Acknowledgementmentioning

confidence: 99%

Sizable Excitonic Effects Undermining the Photocatalytic Efficiency of β-Cu₂V₂O₇

Wiktor

Reshetnyak

Strach

et al. 2018

J. Phys. Chem. Lett.

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Copper vanadates have been proposed as promising photoanodes for water-splitting photoelectrochemical cells, but their performance has recently been shown to be severely limited. To understand this behavior, we study the electronic structure and the optical properties of β-CuVO both experimentally and computationally. The measured absorption spectrum shows an absorption peak at 1.5 eV followed by the onset of an apparent continuum at 2.26 eV, as generally found for this class of materials. We perform calculations within the framework of the QS GW̃ method and the Bethe-Salpeter equation while including effects of magnetic ordering, nuclear quantum motion, and thermal vibrations. We demonstrate the occurrence of two kinds of excitons with high binding energies upon optical excitation in β-CuVO, which account for the first absorption peak and the lower edge of the apparent continuum. The results are confirmed by photoluminescence measurements, where sub-band-gap emissions are found for both excitons. These results provide an explanation for the low photocatalytic efficiencies of copper vanadates, despite the favorable size of their optical band gaps.

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Section: Acknowledgementmentioning

confidence: 99%

Sizable Excitonic Effects Undermining the Photocatalytic Efficiency of β-Cu₂V₂O₇

Wiktor

Reshetnyak

Strach

et al. 2018

J. Phys. Chem. Lett.

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“…Green's function theory in the GW approximation has become the method of choice for the computation of addition and removal energies of valence electrons in solids [40][41][42][43][44][45][46][47][48][49][50][51] and is now increasingly being applied to valence excitations of molecules. 24,[52][53][54][55][56][57][58][59] For the latter, average deviations of less than 0.2 eV from the coupled cluster singles, doubles and perturbative triples [CCSD(T)] reference values have been reported. 60,61 Mean absolute errors for the first IP are even below 0.1 eV when comparing vibrationally resolved GW spectra to experiment.…”

Section: Introductionmentioning

confidence: 99%

Core-Level Binding Energies from GW: An Efficient Full-Frequency Approach within a Localized Basis

Golze

Wilhelm

Setten

et al. 2018

J. Chem. Theory Comput.

118

272

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The GW method is routinely used to predict charged valence excitations in molecules and solids. However, the numerical techniques employed in the most efficient GW algorithms break down when computing core excitations as measured by X-ray photoelectron spectroscopy (XPS). We present a full-frequency approach on the real axis using a localized basis to enable the treatment of core levels in GW. Our scheme is based on the contour deformation technique and allows for a precise and efficient calculation of the self-energy, which has a complicated pole structure for core states. The accuracy of our method is validated by comparing to a fully analytic GW algorithm. Furthermore, we report the obtained core-level binding energies and their deviations from experiment for a set of small molecules and large polycyclic hydrocarbons. The core-level excitations computed with our GW approach deviate by less than 0.5 eV from the experimental reference. For comparison, we also report core-level binding energies calculated by density functional theory (DFT)-based approaches such as the popular delta self-consistent field (ΔSCF) method. Our implementation is optimized for massively parallel execution, enabling the computation of systems up to 100 atoms.

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“…Recently, this approach has been applied to various materials. [10,11] The approach is composed of two procedures; one is the GW approximation (GWA) [12,13] to determine the quasiparticle (QP) energies, which represent the difference between the total energies of the N-electron GS and the (N ± 1)-electron EES. They correspond to photoemission and inverse photoemission spectra (PES/IPES), where one electron is removed from or added to the N-electron GS.…”

Section: Introductionmentioning

confidence: 99%

GW(Γ) method without the Bethe-Salpeter equation for photoabsorption energies of spin-polarized systems

2018

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The one-shot GW method beginning with the local density approximation (LDA) enables one to calculate photoemission and inverse photoemission spectra. In order to calculate photoabsorption spectra, one had to additionally solve the Bethe-Salpeter equation (BSE) for the two-particle (electron-hole) Green's function, which doubly induces the evaluation errors. It has been recently reported that the GW + BSE method significantly underestimates the experimental photoabsorption energies (PAEs) of small molecules. In order to avoid these problems, we propose to apply the GW(Γ) method not to the neutral ground state but to the cationic state to calculate PAEs without solving the BSE, which allows the rigorous one-to-one correspondence between the photoabsorption peak and the "extended" quasiparticle level. We applied the self-consistent LGWΓ method including the vertex correction to our method, and found that this method gives the PAEs of B, Na 3 , and Li 3 within the 0.1 eV accuracy.

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Benchmarking the GW Approximation and Bethe–Salpeter Equation for Groups IB and IIB Atoms and Monoxides

Cited by 40 publications

References 75 publications

Sizable Excitonic Effects Undermining the Photocatalytic Efficiency of β-Cu₂V₂O₇

Sizable Excitonic Effects Undermining the Photocatalytic Efficiency of β-Cu₂V₂O₇

Core-Level Binding Energies from GW: An Efficient Full-Frequency Approach within a Localized Basis

GW(Γ) method without the Bethe-Salpeter equation for photoabsorption energies of spin-polarized systems

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Benchmarking the GW Approximation and Bethe–Salpeter Equation for Groups IB and IIB Atoms and Monoxides

Cited by 40 publications

References 75 publications

Sizable Excitonic Effects Undermining the Photocatalytic Efficiency of β-Cu2V2O7

Sizable Excitonic Effects Undermining the Photocatalytic Efficiency of β-Cu2V2O7

Core-Level Binding Energies from GW: An Efficient Full-Frequency Approach within a Localized Basis

GW(Γ) method without the Bethe-Salpeter equation for photoabsorption energies of spin-polarized systems

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Sizable Excitonic Effects Undermining the Photocatalytic Efficiency of β-Cu₂V₂O₇

Sizable Excitonic Effects Undermining the Photocatalytic Efficiency of β-Cu₂V₂O₇