Magnetic and pairing correlations in coupled Hubbard planes

Scalettar, Richard; Cannon, Joel W.; Scalapino, D. J.; Sugar, R.

doi:10.1103/physrevb.50.13419

Cited by 55 publications

(49 citation statements)

References 27 publications

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“…Thus, the magnetic fluctuations of the two inequivalent planes with different carrier concentration tend to be equalized by interplane coupling effects. A related effect has been detected also in Quantum-MonteCarlo simulations of coupled Hubbard planes carried out by Scalettar et al 19 , in which the two planes have different chemical potentials and one plane is adjusted to half filling. In this case, the antiferromagnetic susceptibility of the half-filled plane is reduced by the coupling with the doped plane.…”

Section: Relation To Experimentsmentioning

confidence: 85%

“…Finally, in a futher step, based on the findings of this paper, it is of interest to investigate the behavior of two coupled, but inequivalent layers in the superconducting state (some work in this direction, although at much higher temperatures, has been carried out in Ref. 19). This may reveal, why the material Y 2 Ba 4 Cu 7 O 15 exhibits a higher T c than both of the corresponding parent compounds it consists of.…”

Section: Discussionmentioning

confidence: 99%

“…These authors also discuss that the 41 meV excitation observed in superconducting YBa 2 Cu 3 O 7 is a collective mode pulled down below the superconducting gap by interactions, and that the observed antisymmetry under interchange of planes follows from the nonnegligible value of J ⊥ . An analysis of the coupling between an undoped layer and an underdoped one, similar in spirit to ours, has been carried out by Scalettar et al 19 . These authors study the pairing mechanism, which arises from the coupling of holes in doped layers to spin fluctuations in the undoped layers in analogy with the Ginzburg-type scenario for the coupling of electrons through excitons in a doped semiconductor.…”

Section: Introductionmentioning

confidence: 99%

“…also Scalettar et al 19 ). This is a suitable model to describe the peculiarity of the 247 compound Y 2 Ba 4 Cu 7 O 15 , whose bilayers are build up of one CuO 2 layer belonging to an YBa 2 Cu 3 O 7 block and one to a YBa 2 Cu 4 O 8 block.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic fluctuations in coupled inequivalent Hubbard layers as a model for

et al. 1999

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We investigate, within the fluctuation-exchange approximation, a correlated-electron model for Y2Ba4Cu7O15 represented by two inequivalent Hubbard layers coupled by an interlayer hopping t ⊥ . An energy offset δ is introduced in order to produce a different charge carrier concentration in the two layers. We compare several single-particle and magnetic excitations, namely, the single particle scattering rate, the spectral function and the spin lattice as well as spin-spin relaxation times in the two layers as a function of δ. We show that the induced interlayer magnetic coupling produces a tendency to "equalization" of the magnetic properties in the two layers whereby antiferromagnetic fluctuations are suppressed in the less doped layer and enhanced in the heavily doped one. The strong antiferromagnetic bilayer coupling causes the charge carriers in the plane with larger doping concentration to behave similar to those of the underdoped layer, they are coupled to. This effect grows for decreasing temperature. For high temperatures or if both layers are optimally or overdoped, i.e. when the antiferromagnetic correlation length becomes of the order or smaller than one lattice site the charge carrier and magnetic dynamics of the two layers is disconnected and the equalization effect disappears. These results are in good agreement with NMR experiments on Y2Ba4Cu7O15 by Stern et al. Phys. Rev B 51, 15478 (1995). We also compare the results with calculations on bilayer systems with equivalent layers as models for the constituent compounds YBa2Cu3O7 and YBa2Cu4O8.

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Section: Relation To Experimentsmentioning

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Magnetic fluctuations in coupled inequivalent Hubbard layers as a model for

et al. 1999

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“…As a matter of fact, this question has been already addressed several times in connection with high T c superconductors, specifically analyzing a bilayer Hubbard model by various techniques, including quantum Monte Carlo 41,42,43,44,45 (QMC) and DMFT 46,47 . In section II we shall discuss more in detail these early works while introducing the model.…”

Section: Introductionmentioning

confidence: 99%

Superconductivity in the doped bilayer Hubbard model

2009

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We study by the Gutzwiller approximation the melting of the valence bond crystal phase of a bilayer Hubbard model at sufficiently large inter-layer hopping. We find that a superconducting domain, with order parameter d z 2 −r 2 , z being the inter-layer direction and r the intra-layer one, is stabilized variationally close to the half-filled non-magnetic Mott insulator. Superconductivity exists at half-filling just at the border of the Mott transition and extends away from half-filling into a whole region till a critical doping, beyond which it gives way to a normal metal phase. This result suggests that superconductivity should be unavoidably met by liquefying a valence bond crystal, at least when each layer is an infinite coordination lattice and the Gutzwiller approximation becomes exact. Remarkably, this same behavior is well established in the other extreme of two-leg Hubbard ladders, showing it might be of quite general validity.

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