On the oxygen isotope effect and apex anharmonicity in high-T c cuprates

Müller, K. A.

doi:10.1007/bf01357502

Cited by 205 publications

(80 citation statements)

References 57 publications

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“…In Fig. 1a, we plot the doping dependence of T c for the 16 18 O. It is evident that the planar oxygen mainly (> 80%) contributes to the total oxygen-isotope shift in the optimally doped cuprate.…”

Section: Isotope Effect On the Superconducting Transition Temperamentioning

confidence: 99%

“…A comprehensive review was given by Franck [17]. The role of the anharmonicity of the apical oxygen on the isotope effect was discussed in detail by Müller [18]. Most of the studies reported so far concern the oxygen-isotope shift (OIS) of T c by replacing 16 O with 18 O, partly because the experimental procedures are simple and reliable.…”

Section: Isotope Effect On the Superconducting Transition Temperamentioning

confidence: 99%

“…The role of the anharmonicity of the apical oxygen on the isotope effect was discussed in detail by Müller [18]. Most of the studies reported so far concern the oxygen-isotope shift (OIS) of T c by replacing 16 O with 18 O, partly because the experimental procedures are simple and reliable. Now it is generally accepted that optimally-doped cuprates exhibit a small and positive oxygen-isotope exponent α O .…”

Section: Isotope Effect On the Superconducting Transition Temperamentioning

confidence: 99%

“…9. It is clear that T c is lower for the 18 More interestingly, the inplane penetration depth λ ab (T ) can be extracted from field-dependent measurements [42]. Fig.…”

Section: Large Oxygen-isotope Effect On the Effective Supercarriementioning

confidence: 99%

“…Of particular interest is the characterisitc temperature T p which strongly depends on the oxygenisotope mass. Upon replacing 16 O by 18 O, T p changes from 170 K to 220 K, i.e., there is a large oxygen-isotope effect on T p (≈ 50 K). Similarly, a large copper-isotope effect on T p has been found in the same compound [53].…”

Section: Huge Oxygen-isotope Effect On the Charge Stripe Formationmentioning

confidence: 99%

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Unconventional isotope effects in the high-temperature cuprate superconductors

Zhao

Keller

Conder

2001

J. Phys.: Condens. Matter

139

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We review various isotope effects in the high-Tc cuprate superconductors to assess the role of the electron-phonon interaction in the basic physics of these materials. Of particular interest are the unconventional isotope effects on the supercarrier mass, on the charge-stripe formation temperature, on the pseudogap formation temperature, on the EPR linewidth, on the spin-glass freezing temperature, and on the antiferromagnetic ordering temperature. The observed unconventional isotope effects strongly suggest that lattice vibrations play an important role in the microscopic pairing mechanism of high-temperature superconductivity.

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Section: Isotope Effect On the Superconducting Transition Temperamentioning

confidence: 99%

Section: Isotope Effect On the Superconducting Transition Temperamentioning

confidence: 99%

Section: Isotope Effect On the Superconducting Transition Temperamentioning

confidence: 99%

“…9. It is clear that T c is lower for the 18 More interestingly, the inplane penetration depth λ ab (T ) can be extracted from field-dependent measurements [42]. Fig.…”

Section: Large Oxygen-isotope Effect On the Effective Supercarriementioning

confidence: 99%

Section: Huge Oxygen-isotope Effect On the Charge Stripe Formationmentioning

confidence: 99%

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Unconventional isotope effects in the high-temperature cuprate superconductors

Zhao

Keller

Conder

2001

J. Phys.: Condens. Matter

139

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Thermodynamics of Pseudospin-Electron Model in Mean Field Approximation

Stasyuk¹,

Danyliv²

2000

phys. stat. sol. (b)

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The mean field type approach based on the self-consistent consideration of an effective field created by electron transfer is developed for a description of thermodynamics of the Hubbard type models with an infinitely large on-site repulsion. This procedure, formulated according to [1], is an extension of the recently proposed generalized random phase approximation(GRPA).Within this approach, the thermodynamic properties of the two-sublattice pseudospin-electron model (the Hubbard model with local anharmonicity) are studied. Such a model can be used for a description of dielectric properties of YBaCuO-type superconductors along c-axis; pseudospins represent anharmonic motions of apical oxygens O4. It is shown that there are either phase transitions in the model with jumps of the mean values of a pseudospin and of electron concentration (in the µ = const regime) or the phase separation (in the n = const regime). The phase transitions or phase separation are caused by pseudospin-pseudospin interaction as well as by electron transfer (the latter results in appearing of effective interaction between pseudospins). The possibility of the ferroelectric type ordering of pseudospins is investigated.

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Anharmonic Excitations, Time Correlations and Electric Conductivity

Chetverikov

Ébeling

Röpke

et al. 2007

Contrib. Plasma Phys.

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We study the influence of anharmonic mechanical excitations of a classical ionic lattice on its electric properties. First, to illustrate salient features, we investigate a simple model, an one-dimensional (1D) system consisting of ten semiclassical electrons embedded in a lattice or a ring with ten ions interacting with exponentially repulsive interactions. The lattice is embedded in a thermal bath. The behavior of the velocity autocorrelation function and the dynamic structure factor of the system are analyzed. We show that in this model the nonlinear excitations lead to long lasting time correlations and, correspondingly, to an increase of the conductivity in a narrow temperature region, where the excitations are supersonic soliton-like. In the second part we consider the quantum statistics of general ion-electron systems with arbitrary dimension and express -following linear response transport theory -the quantum-mechanical conductivity by means of equilibrium time correlation functions. Within the relaxation time approach an expression for the effective collision frequency is derived in Born approximation, which takes into account quantum effects and dynamic effects of the ion motion through the dynamic structure factor of the lattice and the quantum dynamics of the electrons. An evaluation of the influenec of solitons predicts for 1D-lattices a conductivity increase in the temperature region where most thermal solitons are excited, similar as shown in the classical Drude-Lorentz-Kubo framework.

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On the oxygen isotope effect and apex anharmonicity in high-T c cuprates

Cited by 205 publications

References 57 publications

Unconventional isotope effects in the high-temperature cuprate superconductors

Unconventional isotope effects in the high-temperature cuprate superconductors

Thermodynamics of Pseudospin-Electron Model in Mean Field Approximation

Anharmonic Excitations, Time Correlations and Electric Conductivity

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