Proton Diffusion in Perovskite-Type Oxides Based on Small Polaron Model

Tomoyose, Tomozo; Shimoji, Nobuaki; Wakamura, Kunio

doi:10.1143/jpsj.74.3011

Cited by 14 publications

(19 citation statements)

References 20 publications

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“…We find no parabolic relationship in the investigated range of pressure and Raman shift. However, a virtually linear relationship of ν and E a as was found by Wakamura333435 for a wide range of compounds for the OH stretching frequency18 and was found in our study for the Ce–O stretching mode (Supplementary Fig. 1a).…”

Section: Resultssupporting

confidence: 89%

“…Proton conductivity has been interpreted as a polaron-activated process7. Tomoyose et al 18. found that the wave function of a proton between two adjacent oxygen ions in an ABO 3 -type perovskite would spread over the double well potential if the O–O separation was lower than 2.9 Å, with the result that the proton would transfer between the energy minimum sites18.…”

Section: Resultsmentioning

confidence: 99%

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Experimental neutron scattering evidence for proton polaron in hydrated metal oxide proton conductors

Braun

Chen

2017

Nat Commun

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Hydration of oxygen-deficient metal oxides causes filling of oxygen vacancies and formation of hydroxyl groups with interstitial structural protons, rotating around the oxygen in localized motion. Thermal activation from 500 to 800 K triggers delocalization of the protons by jumping to adjacent oxygen ions, constituting proton conductivity. We report quantitative analyses of proton and lattice dynamics by neutron-scattering data, which reveal the interaction of protons with the crystal lattice and proton–phonon coupling. The motion for the proton trapped in the elastic crystal field yields Eigen frequencies and coupling constants, which satisfy Holstein’s polaron model for electrons and thus constitutes first experimental evidence for a proton polaron at high temperature. Proton jump rates follow a polaron model for cerium-oxygen and hydroxyl stretching modes, which are thus vehicles for proton conductivity. This confirms that the polaron mechanism is not restricted to electrons, but a universal charge carrier transport process.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Experimental neutron scattering evidence for proton polaron in hydrated metal oxide proton conductors

Braun

Chen

2017

Nat Commun

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“…. The umbrella‐like reorientation is also recognized by the Japanese school . However, our model emphasizes the ionic property of the system and thus leads to a much smaller difference between E 1 and E 2 in comparison with that obtained in Refs.…”

Section: Domain Of Proton Locationssupporting

confidence: 50%

“…. The earlier theoretical studies based on molecular dynamic approaches , density functional theories as well as model calculations have attained many interesting results . However, discrepancies among results from different theoretical approaches and those from experiments remain.…”

Section: Introductionmentioning

confidence: 99%

Location and lattice dynamics of a proton in the perovskite structure

Deng

Zhang

2016

Phys. Status Solidi B

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A domain of locations of a proton in the perovskite structure is determined by studying the local structure and a hard sphere point charge model. Two intra‐ and one inter‐octahedron processes with different energy barriers of ⟨E1⟩, ⟨E2⟩, and ⟨E3⟩ have been studied, respectively. The order of the energy barriers is predicted as ⟨E3⟩ > ⟨E1⟩ ≥ ⟨E2⟩ by studying both the changes of bonding in these processes and the charge imbalance between the acceptor dopant ion and the B type ion. The inter‐octahedron hopping, ⟨E3⟩, is shown to be a necessary and rate limiting step by using percolation and charge imbalance argument. This result differs with earlier calculations, however, it agrees with the result of quasi‐elastic neutron and other experimental results. Through studying the lattice dynamics of a 1D O–H chain and its monomer, we have developed new formulae for a hydrogen bond system and applied them to explain the experimentally observed red‐shift and broadening of the O–H vibration peak. These phenomena are revealed as indications of the quasi‐free state of a proton instead of the formation of hydrogen bond.

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“…(11). For IHCs, a 0 value may reveal the effects of lattice distortion suggested by Butler et al [44] and Tomoyose et al [45] and also of the ionic radius suggested by Kilner [7].…”

Section: The Relationship Between E Ac and σ(M I / N) Valuesmentioning

confidence: 99%

Proton Diffusion in Perovskite-Type Oxides Based on Small Polaron Model

Cited by 14 publications

References 20 publications

Experimental neutron scattering evidence for proton polaron in hydrated metal oxide proton conductors

Experimental neutron scattering evidence for proton polaron in hydrated metal oxide proton conductors

Location and lattice dynamics of a proton in the perovskite structure

Ion conduction in proton- and related defect (super) ionic conductors: Mechanical, electronic and structure parameters

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