Local electronic structure and high temperature superconductivity

Emery, V. J.; Kivelson, Steven

doi:10.1063/1.59581

Cited by 16 publications

(22 citation statements)

References 34 publications

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“…These charge inhomogeneities are neither due to impurities nor to crystal defects, but are intrinsic to the type of cuprate, producing local lattice distortions in the CuO 2 bond length 10 . In fact, such intrinsic inhomogeneities are also consistent with the presence of charge domains either in a granular [7][8][9] or in a stripe [11][12][13] form.…”

Section: Introductionsupporting

confidence: 59%

“…On the other hand, the zero-point motion of the holes favors delocalization and tends to create phaseseparated states rich either of spin or charge. Experimentally, the stripes are more easily detected in insulating materials, where they are static, but there are evidences of fluctuating stripe correlations in metallic and superconducting compounds 12,11,13 .…”

Section: Introductionmentioning

confidence: 99%

“…The consequence of the microscopic charge inhomogeneities distribution in the CuO 2 planes, either in a striped or in a granular configuration, is the existence of domain walls between the two phases which are spontaneously created in the planes [11][12][13] : regions which are heavily doped or hole-rich may form the stripes and others regions which are hole-poor are created between these charge-rich stripes. The exactly form of these charge distributions is not well known but we can get some insights from a number of recent experiments.…”

Section: The Charge Distributionmentioning

confidence: 99%

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Theory for high-Tcsuperconductors considering inhomogeneous charge distribution

2003

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We propose a general theory for the critical and pseudogap temperatures Tc and T * dependence on the doping concentration for high-Tc oxides, taking into account the charge inhomogeneities in the CuO2 planes. Several recent experiments have revealed that the charge density ρ in a given compound (mostly underdoped) is intrinsic inhomogeneous with large spatial variations which leads to a local charge density ρ(r). These differences in the local charge concentration yield insulator and metallic regions, either in an intrinsic granular or in a stripe morphology. In the metallic region, the inhomogeneous charge density produces also spatial or local distributions which form Cooper pairs at a local superconducting critical temperatures Tc(r) and zero temperature gap ∆0(r). For a given compound, the measured onset of vanishing gap temperature is identified as the pseudogap temperature, that is, T * , which is the maximum of all Tc(r). Below T * , due to the distribution of Tc(r)'s, there are some superconducting regions surrounded by insulator or metallic medium. The transition to a coherent superconducting state corresponds to the percolation threshold among the superconducting regions with different Tc(r)'s. The charge inhomogeneities have been studied by recent STM/S experiments which provided a model for our phenomenological distribution. To make definite calculations and compare with the experimental results, we derive phase diagrams for the BSCO, LSCO and YBCO families, with a mean field theory for superconductivity using an extended Hubbard Hamiltonian. We show also that this novel approach provides new insights on several experimental features of high-Tc oxides.

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Section: Introductionsupporting

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Section: The Charge Distributionmentioning

confidence: 99%

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Theory for high-Tcsuperconductors considering inhomogeneous charge distribution

2003

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“…Unrelated calculations found stripes with different fillings in the t-J model [9], and, using different techniques, in the Hubbard model [10], although other numerical calculations show conflicting results [11,12]. Alternatively, it has been argued that stripes in doped Mott antiferromagnets arise from a tendency towards phase separation, frustrated by electrostatic interactions [13,14]. Stripes in the Hubbard model have also been analyzed within slaveboson techniques, which use the Hartree-Fock solutions as input [15].…”

mentioning

confidence: 99%

Partially filled stripes in the two-dimensional Hubbard model: Statics and dynamics

et al. 2001

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The internal structure of stripes in the two dimensional Hubbard model is studied by going beyond the Hartree-Fock approximation. Partially filled stripes, consistent with experimental observations, are stabilized by quantum fluctuations, included through the Configuration Interaction method. Hopping of short regions of the stripes in the transverse direction is comparable to the bare hopping element. The integrated value of n k compares well with experimental results.By now it is well established that charged stripes are formed in a significant doping range of cuprate oxides [1][2][3]. The existence of these stripes was predicted, on the basis of mean field calculations, in advance of its observation, both in the one [4][5][6][7] and the three bands Hubbard model [8]. This is one of the scarce theoretical results in the field of high-T c superconductivity which was confirmed after its prediction. Interest in these calculations decreased, as it was generally understood that the Hartree-Fock approximation was unable to obtain the partially filled stripes observed experimentally. Unrelated calculations found stripes with different fillings in the t-J model [9], and, using different techniques, in the Hubbard model [10], although other numerical calculations show conflicting results [11,12]. Alternatively, it has been argued that stripes in doped Mott antiferromagnets arise from a tendency towards phase separation, frustrated by electrostatic interactions [13,14]. Stripes in the Hubbard model have also been analyzed within slaveboson techniques, which use the Hartree-Fock solutions as input [15].In the present work we show that the mean field calculations, initially used to demonstrate the existence of stripes, can be systematically improved in order to study the partially filled stripes observed experimentally. In addition, they provide significant insight into the internal structure of the stripes and their fluctuations in the transverse direction. The Hartree-Fock method can be considered a quasiclassical approximation to the spin and charge degrees of freedom. Their low amplitude quantum fluctuations can be incorporated by using the Random Phase Approximation [16]. In addition, one needs to consider quantum tunneling processes between degenerate, or nearly degenerate, Hartree-Fock solutions, when there are many. This is achieved with the Configuration Interaction method (CI), widely used in quantum chemistry [17,18]. The combination of the Hartree-Fock and CI methods gives reasonable results even when applied to one dimensional systems [19]. The CI method restores the symmetries broken by the Hartree-Fock approximation, and provides information on the quantum dynamics of the static solutions obtained in mean field, which can be broadly classified into spin polarons or stripes.Previous mean field studies have focused on filled stripes [7], which tend to be the solutions with the lowest energy per hole in this approximation, especially for the values of U/t ∼ 4 used in the initial studies [4][5][6][7]. There are,...

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“…61 This is accomplished in three stages: a) the formation of charge inhomogeneity (stripes), b) the creation of local spin pairs, and c) the establishment of a phasecoherent state. In general, their approach to the SC in cuprates is correct.…”

Section: The Mcs Modelmentioning

confidence: 99%

Phenomenological model of high-Tc superconductivity: a MCS model

Mourachkine¹

2000

Physica C: Superconductivity

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Since the introduction of a MCS (Magnetic Coupling between Stripes) phenomenological model [cond-mat/9902355, to be published in J. Superconductivity] for hole-doped cuprates many new experimental data have been presented in the literature as evidence in support of the MCS model. We consider here recent data and the MCS model which is based upon experimental facts, namely, the presence of (i) stripes; (ii) spin fluctuations, and (iii) two order parameters (for pairing and for long-phase coherence) in hole-doped cuprates. We discuss also the superconductivity in the s-wave Nd 2-x Ce x CuO 4 cuprate.

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Local electronic structure and high temperature superconductivity

Cited by 16 publications

References 34 publications

Theory for high-Tcsuperconductors considering inhomogeneous charge distribution

Theory for high-Tcsuperconductors considering inhomogeneous charge distribution

Partially filled stripes in the two-dimensional Hubbard model: Statics and dynamics

Phenomenological model of high-Tc superconductivity: a MCS model

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