Influence of next-nearest-neighbor electron hopping on the static and dynamical properties of the two-dimensional Hubbard model

Duffy, Daniel J.; Moreo, Adriana

doi:10.1103/physrevb.52.15607

Cited by 67 publications

(73 citation statements)

References 39 publications

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“…These features are qualitatively consistent with the inelastic neutron scattering for La 2−x Sr x CuO 4 [ 75,76] and Nd 2−x Ce x CuO 4−y [ 79]. The same result for the electron-doped cuprates has been reported by the numerical studies on the Hubbard model [ 16,426] and t-J model [ 427].…”

Section: Magnetic Propertiessupporting

confidence: 88%

Theory of superconductivity in strongly correlated electron systems

et al. 2003

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In this article we review essential natures of superconductivity in strongly correlated electron systems (SCES) from a universal point of view. First we summarize experimental results on SCES by focusing on typical materials such as cuprates, BEDT-TTF organic superconductors, and ruthenate Sr 2 RuO 4 . Experimental results on other important SCES, heavy-fermion systems, will be reviewed separately. The formalism to discuss superconducting properties of SCES is shown based on the Dyson-Gor'kov equations. Here two typical methods to evaluate the vertex function are introduced: One is the perturbation calculation up to the third-order terms with respect to electron correlation. Another is the fluctuationexchange (FLEX) method based on the Baym-Kadanoff conserving approximation. The results obtained by the FLEX method are in good agreement with those obtained by the perturbation calculation. In fact, a reasonable value of T c for spin-singlet d-wave superconductivity is successfully reproduced by using both methods for SCES such as cuprates and BEDT-TTF organic superconductors. As for Sr 2 RuO 4 exhibiting spin-triplet superconductivity, it is quite difficult to describe the superconducting transition by using the FLEX calculation. However, the superconductivity can be naturally explained by the perturbation calculation, since the third-order terms in the anomalous self-energy play the essential role to realize the triplet superconductivity. Another important purpose of this article is to review anomalous electronic properties of SCES near the Mott transition, since the nature of the normal state in SCES has been one of main issues to be discussed. Especially, we focus on pseudogap phenomena observed in under-doped cuprates and organic superconductors. A variety of scenarios to explain the pseudogap phenomena based on the superconducting and/or spin fluctuations are critically reviewed and examined in comparison with experimental results. According to the recent theory, superconducting fluctuations, inherent in the quasi-two-dimensional and strong-coupling superconductors, are the origin of the pseudogap formation. In these compounds, superconducting fluctuations induce a kind of resonance between the Fermi-liquid quasi-particle and the Cooper-pairing states. This resonance gives rise to a large damping effect of quasi-particles and reduces the spectral weight near the Fermi energy. We discuss the magnetic and transport properties as well as the single-particle spectra in the pseudogap state by the microscopic theory of the superconducting fluctuations. As for heavy-fermion superconductors, experimental results are reviewed and several theoretical analyses on the mechanism are provided based on the same viewpoint as explained above.

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Section: Magnetic Propertiessupporting

confidence: 88%

Theory of superconductivity in strongly correlated electron systems

et al. 2003

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“…Numerous analytical and numerical calculations, however, have demonstrated that this degeneracy is an artifact of the mean-field treatment [5,29,[33][34][35] -the actual fermionic dispersion possesses a maximum at (π/2, π/2) and symmetry related points. Recent photoemission experiments on Sr 2 CuO 2 Cl 2 confirmed this result and in addition have shown that the dispersion near the top of the valence band is nearly isotropic around (π/2, π/2) [26,27].…”

Section: B Resonance Near ω (1) Resmentioning

confidence: 99%

Resonant Raman scattering in antiferromagnets

Morr

Chubukov

1997

Phys. Rev. B

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Two-magnon Raman scattering provides important information about electronic correlations in the insulating parent compounds of high-Tc materials. Recent experiments have shown a strong dependence of the Raman signal in B1g geometry on the frequency of the incoming photon. We present an analytical and numerical study of the Raman intensity in the resonant regime. It has been previously argued by one of us (A.Ch) and D. Frenkel that the most relevant contribution to the Raman vertex at resonance is given by the triple resonance diagram. We derive an expression for the Raman intensity in which we simultaneously include the enhancement due to the triple resonance and a final state interaction. We compute the two-magnon peak height (TMPH) as a function of incident frequency and find two maxima at ω (1) res ≈ 2∆ + 3J and ω (2) res ≈ 2∆ + 8J. We argue that the high-frequency maximum is cut only by a quasiparticle damping, while the low-frequency maximum has a finite amplitude even in the absence of damping. We also obtain an evolution of the Raman profile from an asymmetric form around ω (1) res to a symmetric form around ω (2) res . We further show that the TMPH depends on the fermionic quasiparticle damping, the next-nearest neighbor hopping term t ′ and the corrections to the interaction vertex between light and the fermionic current. We discuss our results in the context of recent experiments by Blumberg et al. on Sr2CuO2Cl2 and Y Ba2Cu3O6.1 and Rübhausen et al. on P rBa2Cu3O7 and show that the triple resonance theory yields a qualitative and to some extent also quantitative understanding of the experimental data.

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“…The criteria used here to obtain the most probable locus of the FS from numerical n(q) data are two: (a) find the values of q where n(q) ≈ 0.5 [11] and (b) find the values of q where n(q) changes the most rapidly [20]. For the case of t ′ /t=-0.25 we have observed that both methods provide similar results in the regions close to the diagonal direction in the Brillouin zone, but substantial differences were observed close to the (0, π) and (π, 0) points.…”

Section: B Fermi Surfacementioning

confidence: 99%

Spin and charge fluctuations in theU−t−t′model

Buhler

Moreo

1999

Phys. Rev. B

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As additional neutron scattering experiments are performed on a variety of high temperature superconducting compounds it appears that magnetic incommensuration is a phenomenon common to all of the samples studied. The newest experimental results indicate that incommensurate peaks exist at momentum q = π(1, 1 ± δ) and π(1 ± δ, 1) in La2−xSrxCuO4 (LSCO) and YBa2Cu3O 7−δ (YBCO). The dependence of δ with hole doping appears to be similar in both materials. In addition, new ARPES data for LSCO as a function of doping show that its Fermi surface is qualitatively similar to the one of YBCO, contrary to what was previously believed. Early theoretical attempts to explain LSCO and YBCO behavior usually relied on one-or three-band Hubbard models or the t-J model with electron hopping beyond nearest-neighbor and with different parameter values for each material. In this paper it is shown that using a one band Hubbard U-t-t ′ model with a unique set of parameters, U/t=6 and t ′ /t=-0.25, good agreement is obtained between computational calculations and neutron scattering and ARPES experiments for LSCO and YBCO. It is also shown that using a more negative t ′ /t will induce short-range magnetic incommensuration along the diagonal direction in the Brillouin zone, in qualitative disagreement with the experimental results. At the finite temperatures of the present Monte Carlo simulation it is also observed that in this model the tendency to incommensuration appears to be more related to the shape of the two-dimensional Fermi surface and the strength of the interaction, rather than to charge order.

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Influence of next-nearest-neighbor electron hopping on the static and dynamical properties of the two-dimensional Hubbard model

Cited by 67 publications

References 39 publications

Theory of superconductivity in strongly correlated electron systems

Theory of superconductivity in strongly correlated electron systems

Resonant Raman scattering in antiferromagnets

Spin and charge fluctuations in theU−t−t′model

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