First-Principles<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="italic">T</mml:mi></mml:math>-Matrix Theory with Application to the 6 eV Satellite in Ni

Springer, Mitchell G.; Aryasetiawan, Ferdi; Karlsson, K.

doi:10.1103/physrevlett.80.2389

Cited by 94 publications

(89 citation statements)

References 22 publications

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“…Other methods for including strong correlations, such as the Hubbard model, Hubbard plus GW , or T −matrix methods have been used in calculations of XAS and XPS, and could be adapted for calculations of RIXS as well. 45,46 Yet another approach for including strong correlations relevant to this discussion is multi-configurational multiple-scattering theory. 47 This method has already been used to account for mixing of the core-holes in XAS, and could be extended to calculations of RIXS.…”

Section: Discussionmentioning

confidence: 99%

Real-space Green’s function approach to resonant inelastic x-ray scattering

et al. 2011

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We present an ab initio theory of core and valence resonant inelastic x-ray scattering (RIXS) based on a real-space multiple scattering Green's function formalism and a quasi-boson model Hamiltonian. Simplifying assumptions are made which lead to an approximation of the RIXS spectrum in terms of a convolution of an effective x-ray absorption signal with the x-ray emission cross-section. Additional many body corrections are incorporated in terms of an effective energy dependent spectral function. Example calculations of RIXS are found to give qualitative agreement with experimental data. Our approach also yields simulations of lifetime-broadening suppressed XAS, as observed in high energy resolution fluorescence detection experiment (HERFD). Finally possible improvements to our approach are briefly discussed.

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Section: Discussionmentioning

confidence: 99%

Real-space Green’s function approach to resonant inelastic x-ray scattering

et al. 2011

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“…20 The calculations by Zhukov et al 18 and Bacelar et al 19 showed that the evaluated lifetimes also strongly vary along the 4d-series following trends in electronic structure. The extension, GW + T , of the GW approximation by inclusion of multiple electron-hole scattering within a T-matrix approximation 21,22,23,24,25 results in the decrease of the GW lifetime value that brings theory and experiment to better agreement. 12,24,25 In this paper we perform TR-2PPE measurements of excited electron lifetimes in Mo and Rh and compare these results with the GW and GW + T calculated lifetimes.…”

Section: Introductionmentioning

confidence: 99%

Experimental time-resolved photoemission andab initiostudy of lifetimes of excited electrons in Mo and Rh

et al. 2006

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We have studied the relaxation dynamics of optically excited electrons in molybdenum and rhodium by means of time resolved two-photon photoemission spectroscopy (TR-2PPE) and ab initio electron self-energy calculations performed within the GW and GW + T approximations. Both theoretical approaches reproduce qualitatively the experimentally observed trends and differences in the lifetimes of excited electrons in molybdenum and rhodium. For excitation energies exceeding the Fermi energy by more than 1 eV, the GW + T theory yields lifetimes in quantitative agreement with the experimental results. As one of the relevant mechanisms causing different excited state lifetime in Mo and Rh we identify the occupation of the 4d bands. An increasing occupation of the 4d bands results in an efficient decrease of the lifetime even for rather small excitation energies of a few 100 meV.

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“…One can then generate particle number conserving approximations when combining many-body methods, such as GW + T-matrix [42] and the FLEX approximation [43,44], provided that each diagram is consistently dressed.…”

Section: Number Conservationmentioning

confidence: 99%

Partial self-consistency and analyticity in many-body perturbation theory: Particle number conservation and a generalized sum rule

Karlsson

Leeuwen

2016

Phys. Rev. B

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We consider a general class of approximations which guarantees the conservation of particle number in many-body perturbation theory. To do this we extend the concept of Φ-derivability for the self-energy Σ to a larger class of diagrammatic terms in which only some of the Green's function lines contain the fully dressed Green's function G. We call the corresponding approximations for Σ partially Φ-derivable. A special subclass of such approximations, which are gauge-invariant, is obtained by dressing loops in the diagrammatic expansion of Φ consistently with G. These approximations are number conserving but do not have to fulfill other conservation laws, such as the conservation of energy and momentum. From our formalism we can easily deduce if commonly used approximations will fulfill the continuity equation, which implies particle number conservation. We further show how the concept of partial Φ-derivability plays an important role in the derivation of a generalized sum rule for the particle number, which reduces to the Luttinger-Ward theorem in the case of a homogeneous electron gas, and the Friedel sum rule in the case of the Anderson model. To do this we need to ensure that the Green's function has certain complex analytic properties, which can be guaranteed if the spectral function is positive semi-definite. The latter property can be ensured for a subset of partially Φ-derivable approximations for the self-energy, namely those that can be constructed from squares of so-called half-diagrams. In case the analytic requirements are not fulfilled we highlight a number of subtle issues related to branch cuts, pole structure and multivaluedness. We also show that various schemes of computing the particle number are consistent for particle number conserving approximations.

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First-PrinciplesT-Matrix Theory with Application to the 6 eV Satellite in Ni

Cited by 94 publications

References 22 publications

Real-space Green’s function approach to resonant inelastic x-ray scattering

Real-space Green’s function approach to resonant inelastic x-ray scattering

Experimental time-resolved photoemission andab initiostudy of lifetimes of excited electrons in Mo and Rh

Partial self-consistency and analyticity in many-body perturbation theory: Particle number conservation and a generalized sum rule

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