Evidence for strong lattice effects as revealed from huge unconventional oxygen isotope effects on the pseudogap temperature in 
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Bendele, M.; Rohr, Fabian von; Guguchia, Zurab; Pomjakushina, E.; Conder, K.; Bianconi, A.; Simon, Arndt; Bussmann‐Holder, A.; Keller, H.

doi:10.1103/physrevb.95.014514

Cited by 27 publications

(25 citation statements)

References 48 publications

(92 reference statements)

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“…The isotopic effect at the ordering temperature [38][39][40] of polaron stripes [41] has also provided compelling evidence that local lattice fluctuations and given experimental support for the polaronic proposal of Alex Muller [33]. The fact that the size of the SC coherence lengths are generally less than λ CO also suggests that valence electrons form lattice-induced Cooper pairs in CO domains.…”

Section: Resultsmentioning

confidence: 94%

Scaling between Superfluid Density and Tc in Overdoped La2−xSrxCuO4 Films

Mello

2019

Condensed Matter

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We used an electronic phase separation approach to interpret the scaling between the low-temperature superfluid density average ρ sc ( 0 ) and the superconducting critical temperature T c on overdoped La 2 − x Sr x CuO 4 films. Guided by the observed nematic and incommensurate charge ordering (CO), we performed simulations with a free energy that reproduces charge domains with wavelength λ C O and provides a scale to local superconducting interactions. Under these conditions a complex order parameter with amplitude Δ d ( r i ) and phase θ ( r i ) may develop at a domain i. We assumed that these domains are coupled by Josephson energy E J ( r i j ) , proportional to the local superfluid density ρ sc ( r i j ) . Long-range order occured when the average E J ( T c ) is ∼ k B T c . The linear ρ s c ( 0 ) vs. T c relation was satisfied whenever CO was present, even with almost vanishing charge amplitudes.

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Section: Resultsmentioning

confidence: 94%

Scaling between Superfluid Density and Tc in Overdoped La2−xSrxCuO4 Films

Mello

2019

Condensed Matter

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“…Hence, depending on the value of the phonon frequency

coefficient

can have any sign and the value:

for

and

for

For

, the isotope coefficient becomes infinite:

The results obtained suggest that the isotope exponent diverges for

, i.e., for

( Figure 2 ). Great negative values of the isotope coefficient in the pseudogap state were observed experimentally in [ 18 , 19 , 20 ]. It should be noted that in some cases, negative values of the isotope coefficient were also observed in ordinary SC [ 21 ], which exceeded in modulus the value of the isotope coefficient in monoatomic systems α=0.5 yielded by the BCS.…”

Section: Isotope Coefficient For the Pseudogap Phasementioning

confidence: 87%

Pseudogap Isotope Effect as a Probe of Bipolaron Mechanism in High Temperature Superconductors

Лахно

2021

Materials

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A theory of a pseudogap phase of high-temperature superconductors where current carriers are translation invariant bipolarons is developed. A temperature of T* a transition from a pseudogap phase to a normal one is calculated. For the temperature of a transition to the pseudogap phase, the isotope coefficient is found. It is shown that the results obtained, in particular, the possibility of negative values of the isotope coefficient, are consistent with the experiment. New experiments on the influence of the magnetic field on the isotope coefficient are proposed.

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“…In 2017, by using X‐ray absorption near edge structure (XANES), ref. [] shows a remarkably large and strongly doping dependent oxygen isotope ( 16 O vs 18 O) effect on the pseudogap temperature of

{La}_{2 - x} {Sr}_{x} {CuO}_{4}

, demonstrating “a substantial involvement of the lattice in the formation of the pseudogap, consistent with a polaronic approach to cuprate superconductivity.” See also discussions in refs. [].…”

Section: Experimental Foundations Of Our Microscopic Approachmentioning

confidence: 87%

“…This is also confirmed in the key experiments (and the references therein) for Bi2212 and refs. [] for La‐based cuprate superconductors (

{La}_{2 - x} {Ba}_{x} {CuO}_{4}

{La}_{2 - x} {Sr}_{x} {CuO}_{4}

, La 2 CuO 4.1 ). For instance, ref.…”

Section: Experimental Foundations Of Our Microscopic Approachmentioning

confidence: 99%

Isotropic Bipolaron–Fermion Exchange Theory and Unconventional Pairing in Cuprate Superconductors

2018

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The appearance of unconventional pairing in superconducting cuprates is examined from a microscopic model, taking into account important properties of hole-doped copper oxides. An exchange interaction between fermions and dominantly inter-site bipolarons is considered to be the mechanism which leads to the pairing. Its momentum dependency is connected to the well-established fermion-phonon anomalies in cuprate superconductors. Since charge carriers in these materials are strongly correlated, a screened Coulomb repulsion is added to this exchange term. Any ad hoc assumptions like anisotropy are avoided, but a microscopic explanation of unconventional pairing for coupling strengths that are in accordance with experimental facts is provided. One important outcome is a mathematically rigorous elucidation of the role of Coulomb repulsion in unconventional pairing, which is shown to be concomitant with a strong depletion of superconducting pairs. The theory, applied to the special case of LaSr 214, predicts at optimal doping i) a coherence length of 21Å, which is the same as that obtained from the Ginzburg-Landau critical magnetic field measured for this material, and ii) d-wave pair formation in the pseudogap regime, that is, at temperatures much higher than the superconducting transition temperature.

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Evidence for strong lattice effects as revealed from huge unconventional oxygen isotope effects on the pseudogap temperature in La2−xSrxCuO4

Cited by 27 publications

References 48 publications

Scaling between Superfluid Density and Tc in Overdoped La2−xSrxCuO4 Films

Scaling between Superfluid Density and Tc in Overdoped La2−xSrxCuO4 Films

Pseudogap Isotope Effect as a Probe of Bipolaron Mechanism in High Temperature Superconductors

Isotropic Bipolaron–Fermion Exchange Theory and Unconventional Pairing in Cuprate Superconductors

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