Electronic structure and electron-phonon interaction in transition metal oxides with d0 configuration and lightly doped compounds

Fujimori, A.; Bocquet, A. E.; Morikawa, Kyojiro; Kobayashi, Katsuyoshi; Saitoh, T.; Tokura, Y.; Hase, Izumi; Onoda, Mitsuko

doi:10.1016/0022-3697(96)00001-7

Cited by 47 publications

(52 citation statements)

References 30 publications

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“…In the latter case, the mass for nonlocal EPI at λ = 1.1λ c is one order of magnitude lighter: diagonal m d (along k x = k y ) and transverse m t (along k x = −k y ) masses for local EPI are m d = 71.4 and m t = 65.7 whereas for nonlocal EPI their values are m d = 7.1 and m t = 7.5, respectively, in units of the bare effective masses (g = g 1 = 0). Similar effects have been discussed in a number of different models [13,20]. Figure 4b and 4c show the dependence of spin deviation and the contribution to the kinetic energy arising due to magnon assisted NN hoppings, K t , on the dimensionless coupling constant λ.…”

supporting

confidence: 65%

Nonlocal Composite Spin-Lattice Polarons in High Temperature Superconductors

et al. 2007

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The non-local nature of the polaron formation in t-t ′ -t ′′ -J model is studied in large lattices up to 64 sites by developing a new numerical method. We show that the effect of longer-range hoppings t ′ and t ′′ is a large anisotropy of the electron-phonon interaction (EPI) leading to a completely different influence of EPI on the nodal and antinodal points in agreement with the experiments. Furthermore, nonlocal EPI preserves polaron's quantum motion, which destroys the antiferromagnetic order effectively, even at strong coupling regime, although the quasi-particle weight in angleresolved-photoemission spectroscopy is strongly suppressed.PACS numbers: 71.10. Fd, 02.70.Ss, 75.50.Ee It is a matter of long debates whether electron-phonon interaction (EPI) plays an essential role in the formation of the puzzling properties of high temperature superconductors [1]. Early theoretical studies of the angle resolved photoemission spectroscopy (ARPES) of undoped cuprates were based on the t-t ′ -t ′′ -J model, where doped holes into an antiferromagnetic (AFM) material are characterized by exchange constant J and hoppings up to 3rd near neighbors(NN) with amplitudes t, t ′ and t ′′ . This approach successfully described the dispersion of the experimentally observed peak [2] and appeared to exclude strong EPI. However, there was a strong contradiction between the theoretical and experimental lineshapes: in contrast with the very broad peak in experiments [1] the theory predicted a sharp peak [3,4,5]. This contradiction was resolved under assumption that the undoped parent compounds are in the strong coupling regime (SCR) of the EPI. In the simplest case of t-J-Holstein model, where a hole interacts with dispersionless optical phonons through on-site local coupling, it was shown that at SCR the spectral weight of the quasiparticle is almost completely transferred to the broad FranckCondon shake-off peak which inherits the dispersion of the hole when it does not interact with phonons [6]. Furthermore, the inheritance of the dispersion of the noninteracting quasiparticle by the Franck-Condon peak was shown to be a property of a broad class of models with EPI [7]. Recently, the relevance of the t-J-Holstein model for cuprates has been rather convincingly questioned [8]. It has been shown that SCR leads to a picture of a localized static hole with 4 broken bonds about it. In this case the percolative model predicts that AFM order survives up to critical concentration x ≈ 0.5 in contradiction with the experimental value x ≈ 0.02−0.04. Another problem of the t-J-Holstein model is the very large effective mass in the whole SCR [6] contradicting transport and optical properties of lightly doped cuprates [9].The above arguments, in favor or against the SCR in undoped cuprates, suggest that the answer must be found in a class of more realistic t-t ′ -t ′′ -J models where EPI, as it is in cuprates [10], is nonlocal. Besides of the particular relevance of the above models in the physics of high temperature superconductivity, there ...

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confidence: 65%

Nonlocal Composite Spin-Lattice Polarons in High Temperature Superconductors

et al. 2007

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“…Note that this does not correspond to the usual atomic, anti-adiabatic limit [35], where it is assumed from the beginning that D → 0 is the smallest energy scale in the problem, resulting in dispersionless high energy features. The present theory is valid in the opposite limit, D ≫ ω 0 , which is more often realized in solids [36,37,38]. Due to the large transfer integrals between molecular units, the discrete shakeoff spectrum characteristic of isolated molecules is converted here into a continuous gaussian spectral density [16], and a sizeable high-energy dispersion is recovered.…”

Section: B Strong Coupling Limitmentioning

confidence: 81%

“…We shall focus instead on the polaronic adiabatic regime (i.e. moderate to strong electron-boson couplings E P > ∼ D and adiabatic bosons ω 0 ≪ D), which is more often encountered in solids [36,37,38], and for which a simple formulation of the spectral properties is not clearly established.…”

Section: Polaronic Semiconductormentioning

confidence: 99%

Spectral properties and isotope effect in strongly interacting systems: Mott-Hubbard insulator versus polaronic semiconductor

Fratini

Ciuchi

2005

Phys. Rev. B

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We study the electronic spectral properties in two examples of strongly interacting systems: a Mott-Hubbard insulator with additional electron-boson interactions, and a polaronic semiconductor. An approximate unified framework is developed for the high energy part of the spectrum, in which the electrons move in a random field determined by the interplay between magnetic and bosonic fluctuations. When the boson under consideration is a lattice vibration, the resulting isotope effect on the spectral properties is similar in both cases, being strongly temperature and energy dependent, in qualitative agreement with recent photoemission experiments in the cuprates.

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“…In contrast, small polarons form highly localized in-gap states and can hop to adjacent lattice sites when thermally activated 10 . Experimental information on the role of polarons in SrTiO 3 is abundant, yet controversial [11][12][13][14][15][16][17][18][19][20][21][22][23][24] . The key question is whether it is a large or a small polaron that is formed.…”

Section: Introductionmentioning

confidence: 99%

Coexistence of trapped and free excess electrons inSrTiO3

et al. 2015

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The question whether excess electrons in SrTiO3 form free or trapped carriers is a crucial aspect for the electronic properties of this important material. This fundamental ambiguity prevents a consistent interpretation of the puzzling experimental situation, where results support one or the other scenario depending on the type of experiment that is conducted. Using density functional theory with an on-site Coulomb interaction U, we show that excess electrons form small polarons if the density of electronic carriers is higher than ≈ 10 20 cm −3 . Below this value, the electrons stay delocalized or become large polarons. For oxygen-deficient SrTiO3, small polarons confined to Ti 3+ sites are immobile at low temperature but can be thermally activated into a conductive state, which explains the metal-insulator transition observed experimentally.

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Electronic structure and electron-phonon interaction in transition metal oxides with d0 configuration and lightly doped compounds

Cited by 47 publications

References 30 publications

Nonlocal Composite Spin-Lattice Polarons in High Temperature Superconductors

Nonlocal Composite Spin-Lattice Polarons in High Temperature Superconductors

Spectral properties and isotope effect in strongly interacting systems: Mott-Hubbard insulator versus polaronic semiconductor

Coexistence of trapped and free excess electrons inSrTiO3

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