Peierls versus Holstein models for describing electron-phonon coupling in perovskites

Yam, Yau-Chuen; Moeller, Mirko; Sawatzky, G. A.; Berciu, Mona

doi:10.1103/physrevb.102.235145

Cited by 10 publications

(4 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both of these possibilities lead to more challenging calculations and are left for future work. Translating recent advances in polaron models [52] into first-principles calculations may also enable accurate modeling of more delocalized polaron states. Another possibility to describe small polarons delocalized over a few unit cells would be to employ a linear combination of WFs and use a variational approach to minimize the polaron energy.…”

Section: Discussionmentioning

confidence: 99%

Facile ab initio approach for self-localized polarons from canonical transformations

Lee

Chen

Zhou

et al. 2021

Phys. Rev. Materials

View full text Add to dashboard Cite

Electronic states in a crystal can localize due to strong electron-phonon (e-ph) interactions, forming so-called small polarons. Methods to predict the formation and energetics of small polarons are either computationally costly or not geared toward quantitative predictions. Here we show a formalism based on canonical transformations to compute the polaron formation energy and wave function using ab initio e-ph interactions. Comparison of the calculated polaron and band-edge energies allows us to determine whether charge carriers in a material favor a localized small polaron over a delocalized Bloch state. Due to its low computational cost, our approach enables efficient studies of the formation and energetics of small polarons, as we demonstrate by investigating electron and hole polaron formation in alkali halides and metal oxides and peroxides. We outline refinements of our scheme and extensions to compute transport in the polaron hopping regime.

show abstract

Section: Discussionmentioning

confidence: 99%

Facile ab initio approach for self-localized polarons from canonical transformations

Lee

Chen

Zhou

et al. 2021

Phys. Rev. Materials

View full text Add to dashboard Cite

show abstract

“…Our recent work shows that that is not always the case. 27 Even when it is, an even deeper issue is how to properly gauge the strength of the e-ph coupling. This strength can be estimated for the bare hole, but that is not the fermion described by the one-band models.…”

Section: Introductionmentioning

confidence: 99%

Dressing due to correlations strongly reduces the effect of electron-phonon coupling

Yam,

Sawatzky,

Berciu

2022

Preprint

Self Cite

View full text Add to dashboard Cite

We investigate the difference between the coupling of a bare carrier to phonons versus the coupling of a correlations-dressed quasiparticle to phonons, and show that latter may be weak even if the former is strong. Specifically, we analyze the effect of the hole-phonon coupling on the dispersion of the quasiparticle that forms when a single hole is doped into a cuprate layer. To model this, we start from the three-band Emery model supplemented by the Peierls modulation of the p-d and p-p hoppings due to the motion of O ions. We then project onto the strongly correlated U dd → ∞ limit where charge fluctuations are frozen on the Cu site. The resulting effective Hamiltonian describes the motion of a doped hole on the O sublattice, and its interactions with Cu spins and O phonons. We show that even though the hole-phonon coupling is moderate to strong, it leads to only a very minor increase of the quasiparticle's effective mass as compared to its mass in the absence of coupling to phonons, consistent with a weak coupling to phonons of the correlations-dressed quasiparticle. We explain the reasons for this suppression, revealing why it is expected to happen in any systems with strong correlations.

show abstract

“…Any combinations of the above features are straightforward to implement, e.g. g(k, q ) couplings in models with multiple electronic bands [30][31][32] or a mix of g(q ) and g(k, q ) couplings [33,34]. Especially relevant for the consideration of RIXS spectra was the generalization of MA to models that include disorder [35] (the core-hole attraction is a very simple form of disorder).…”

Section: Introductionmentioning

confidence: 99%

Beyond the single-site approximation modeling of electron-phonon coupling effects on resonant inelastic X-ray scattering spectra

2021

Self Cite

View full text Add to dashboard Cite

Resonant inelastic X-ray scattering (RIXS) is used increasingly for characterizing low-energy collective excitations in materials. RIXS is a powerful probe, which often requires sophisticated theoretical descriptions to interpret the data. In particular, the need for accurate theories describing the influence of electron-phonon (e-p) coupling on RIXS spectra is becoming timely, as instrument resolution improves and this energy regime is rapidly becoming accessible. To date, only rather exploratory theoretical work has been carried out for such problems. We begin to bridge this gap by proposing a versatile variational approximation for calculating RIXS spectra in weakly doped materials, for a variety of models with diverse e-p couplings. Here, we illustrate some of its potential by studying the role of electron mobility, which is completely neglected in the widely used local approximation based on Lang-Firsov theory. Assuming that the e-p coupling is of the simplest, Holstein type, we discuss the regimes where the local approximation fails, and demonstrate that its improper use may grossly underestimate the e-p coupling strength.

show abstract

Peierls versus Holstein models for describing electron-phonon coupling in perovskites

Cited by 10 publications

References 46 publications

Facile ab initio approach for self-localized polarons from canonical transformations

Facile ab initio approach for self-localized polarons from canonical transformations

Dressing due to correlations strongly reduces the effect of electron-phonon coupling

Beyond the single-site approximation modeling of electron-phonon coupling effects on resonant inelastic X-ray scattering spectra

Contact Info

Product

Resources

About