From BCS-like superconductivity to condensation of local pairs: A numerical study of the attractive Hubbard model

Singer, J. M.; Pedersen, M. H.; Schneider, T.; Beck, H. P.; Matuttis, Hans‐Georg

doi:10.1103/physrevb.54.1286

Cited by 97 publications

(124 citation statements)

References 28 publications

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“…Notice that the above method of solving the problem corresponds to the strongly type-II regime of a dual superconductor (κ d ≫ 1). In this limit, the CPCDW pattern is primarily given by the dual supercurrent j Φ in the Maxwell equation (40), itself determined by the solution to the Abrikosov-Hofstadter problem (39). The modulation in δB d only reflects this pattern of vortices in j Φ (40), and the dual magnetic energy is only a small fraction of the Abrikosov-Hofstadter condensation energy.…”

Section: Dual Superconductor and Cooper Pair Cdw In Underdoped Cupmentioning

confidence: 99%

“…Consequently, the two descriptions, that of the Cooper pairs versus the real-space pairs, correspond to the two opposite limits of (40,39), the first to the strongly type-II, the second to the strongly type-I limit of a dual superconductor. The density-wave patterns associated with these two limits are generally different and can be distinguished in experiments.…”

Section: Dual Superconductor and Cooper Pair Cdw In Underdoped Cupmentioning

confidence: 99%

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Model of phase fluctuations in a latticed-wave superconductor: Application to the Cooper-pair charge-density wave in underdoped cuprates

Melikyan

Tešanović

2005

Phys. Rev. B

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We introduce and study an XY-type model of thermal and quantum phase fluctuations in a twodimensional correlated lattice d-wave superconductor based on the QED3 effective theory of high temperature superconductors. General features of and selected results obtained within this model were reported earlier in an abbreviated format (Z. Tešanović, cond-mat/0405235). The model is geared toward describing not only the long distance but also the intermediate lengthscale physics of underdoped cuprates. In particular, we elucidate the dynamical origin and investigate specific features of the charge-density-wave of Cooper pairs, which we argue is the state behind the periodic charge density modulation discovered in recent scanning-tunneling-microscopy experiments. We illustrate how Mott-Hubbard correlations near half-filling suppress superfluid density and favor an incompressible state which breaks translational symmetry of the underlying atomic lattice. We show how the formation of the Cooper pair charge-density-wave in such a strongly quantum fluctuating superconductor can naturally be understood as an Abrikosov-Hofstadter problem in a type-II dual superconductor, with the role of the dual magnetic field played by the electron density. The resulting Abrikosov lattice of dual vortices translates into the periodic modulation of the Bogoliubov-deGennes gap function and the electronic density. We numerically study the energetics of various AbrikosovHofstadter dual vortex arrays and compute their detailed signatures in the single-particle local tunneling density of states. A 4×4 checkerboard-type modulation pattern naturally arises as an energetically favored ground state at and near the x = 1/8 doping and produces the local density of states in good agreement with experimental observations.

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Section: Dual Superconductor and Cooper Pair Cdw In Underdoped Cupmentioning

confidence: 99%

Section: Dual Superconductor and Cooper Pair Cdw In Underdoped Cupmentioning

confidence: 99%

Model of phase fluctuations in a latticed-wave superconductor: Application to the Cooper-pair charge-density wave in underdoped cuprates

Melikyan

Tešanović

2005

Phys. Rev. B

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“…The normal state region below this characteristic temperature is referred to as the pseudogap regime, where anomalies are seen in various physical quantities, such as a gap-like structure in single-particle density of states. As the origin of the pseudogap regime, the so-called preformed-pair scenario has been extensively discussed in high-T c cuprates [18][19][20][21][22][23]. However, because of the complexity of this system, other scenarios have been also proposed, such as antiferromagnetic spin fluctuations [24,25], and a hidden order [26].…”

Section: Introductionmentioning

confidence: 99%

Pseudogap temperature and effects of a harmonic trap in the BCS-BEC crossover regime of an ultracold Fermi gas

2011

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We theoretically investigate excitation properties in the pseudogap regime of a trapped Fermi gas. Using a combined T -matrix theory with the local density approximation, we calculate strongcoupling corrections to single-particle local density of states (LDOS), as well as the single-particle local spectral weight (LSW). Starting from the superfluid phase transition temperature T c , we clarify how the pseudogap structures in these quantities disappear with increasing the temperature.As in the case of a uniform Fermi gas, LDOS and LSW give different pseudogap temperatures T * and T * * at which the pseudogap structures in these quantities completely disappear. Determining T * and T * * over the entire BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensate) crossover region, we identify the pseudogap regime in the phase diagram with respect to the temperature and the interaction strength. We also show that the so-called back-bending peak recently observed in the photoemission spectra by JILA group may be explained as an effect of pseudogap phenomenon in the trap center. Since strong pairing fluctuations, spatial inhomogeneity, and finite temperatures, are important keys in considering real cold Fermi gases, our results would be useful for clarifying normal state properties of this strongly interacting Fermi system.

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“…[24,25] Experimentally measurable thermodynamical properties have also been calculated as a function of density and interaction strength across the crossover. [20][21][22] Although, the crossover phenomena is investigated from various different aspects, however a conclusive study on the BCS-BEC crossover in a d-wave SC is still pending.…”

Section: Introductionmentioning

confidence: 99%

Electron pairing and evidence of a BCS–BEC crossover in d-wave superconductors

Das¹,

Khan²,

Basu³

2013

Physica B: Condensed Matter

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We have demonstrated that it is possible to access a crossover scenario starting with a weak coupling (BCS) d-wave superconductor to a strongly coupled Bose-Einstein condensate (BEC) phase as the exchange interaction is tuned in a two dimensional system described by a t-J-U model via numerically solving the Bogoliubov-de Gennes (BdG) equations. While in the extreme dilute limit, the electronic pairing phenomena is independent of the Coulomb repulsion, U , the superconductivity depends on U , and so does the crossover. Further, the effect of variation in the carrier density on the BCS-BEC crossover has also been investigated. The crossover picture is illustrated by computing the chemical potential, which when falls below the noninteracting band minimum, signals the onset of a phase with tightly bound, shorter pairs. As an evidence of the above feature, the Cooper pair radius is calculated which shows a significant shortening at the emergence of a BEC-like phase. Besides, in contrast to the previous work where a crossover was claimed only in the dilute limit, we have demonstrated it at large densities near half filling.

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From BCS-like superconductivity to condensation of local pairs: A numerical study of the attractive Hubbard model

Cited by 97 publications

References 28 publications

Model of phase fluctuations in a latticed-wave superconductor: Application to the Cooper-pair charge-density wave in underdoped cuprates

Model of phase fluctuations in a latticed-wave superconductor: Application to the Cooper-pair charge-density wave in underdoped cuprates

Pseudogap temperature and effects of a harmonic trap in the BCS-BEC crossover regime of an ultracold Fermi gas

Electron pairing and evidence of a BCS–BEC crossover in d-wave superconductors

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