Spin-fluctuation exchange study of superconductivity in two- and three-dimensional single-band Hubbard models

Arita, Ryotaro; Kuroki, Kazuhiko; Aoki, Hideo

doi:10.1103/physrevb.60.14585

Cited by 82 publications

(83 citation statements)

References 34 publications

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“…Namely in this case, spin triplet pairing is expected to dominate strongly over singlet since ferromagnetic spin fluctuations arise for t ′ ∼ 0.5 and n ∼ 2 (or equivalently t ′ ∼ −0.5 and n ∼ 0) due to the large density of states at the Fermi level. This can be considered as well established because a number of approaches, including a FLEX study 31,48 , perturbational studies 49,50 , a T -matrix approximation 51 , and a renormalization group study 29 , reach (at least qualitatively) the same conclusion in this parameter regime. Since pairs may be formed at large distances for dilute career density, here we calculate the pairing interaction vertex also for the singlet sp3 channel shown in the inset of Fig.10(b).…”

Section: Near Full Fillingmentioning

confidence: 84%

Quantum Monte Carlo study of the pairing symmetry competition in the Hubbard model

et al. 2004

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To shed light into the pairing mechanism of possible spin-triplet superconductors (TMTSF)2X and Sr2RuO4, we study the competition among various spin singlet and triplet pairing channels in the Hubbard model by calculating the pairing interaction vertex using the ground state quantum Monte Carlo technique. We model (TMTSF)2X by a quarter-filled quasi-one dimensional (quasi-1D) Hubbard model, and the γ band of Sr2RuO4 by a two dimensional (2D) Hubbard model with a band filling of ∼ 4/3. For the quasi-1D system, we find that triplet f -wave pairing not only dominates over triplet p-wave in agreement with the spin fluctuation theory, but also looks unexpectedly competitive against d-wave. For the 2D system, although the results suggest presence of attractive interaction in the triplet pairing channels, the d-wave pairing interaction is found to be larger than those of the triplet channels.

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Section: Near Full Fillingmentioning

confidence: 84%

Quantum Monte Carlo study of the pairing symmetry competition in the Hubbard model

et al. 2004

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“…One also gets the correct order of magnitude of the superconducting and superfluid transition temperature T c when the model parameters are inferred from experiments in the normal state of the above systems. For the case of a nearly half-filled single band, the calculations showed that the Eliashberg superconducting transition temperature T c is higher for the tetragonal (quasi-2D) than cubic (3D) lattice [3][4][5][6]. Particularly striking is the comparison between the cubic antiferromagnetic metal CeIn 3 and the closely related compound CeCoIn 5 [7].…”

Section: Introductionmentioning

confidence: 98%

Migdal’s theorem and the pseudogap

Monthoux¹

2003

Phys. Rev. B

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We study a model of quasiparticles on a two-dimensional square lattice coupled to Gaussian distributed dynamical molecular fields. We consider two types of such fields, a vector molecular field that couples to the quasiparticle spin-density and a scalar field coupled to the quasiparticle number density. An important feature of the magnetic pseudogap found in the present calculations is that it is strongly anisotropic. It vanishes along the diagonal of the Brillouin zone and is large near the zone boundary. In the case of ferromagnetic fluctuations, we also find a range of model parameters with qualitative changes in the quasiparticle spectral function not captured by the one-loop approximation, in that the quasiparticle peak splits into two. We find that one needs to be closer to the magnetic boundary to observe the pseudogap effects in the nearly ferromagnetic case relative to the nearly antiferromagnetic one, under otherwise similar conditions. We provide intuitive arguments to explain the physical origin of the breakdown of Migdal's theorem.

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“…Scalapino et al have shown, with the random phase approximation, that d x 2 −y 2 pairing gives way to d xy in a three-dimensional cubic lattice when charge fluctuations become large with the introduction of the off-site interaction. 4 However, systematic studies are yet to come for the charge fluctuations, in contrast to the spin-fluctuation mediated superconductivity for which favorable situations for its occurrence has been extensively discussed 5,6 .…”

Section: Introductionmentioning

confidence: 99%

Phase diagram of the two-dimensional extended Hubbard model: Phase transitions between different pairing symmetries when charge and spin fluctuations coexist

et al. 2004

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In order to explore how superconductivity arises when charge fluctuations and spin fluctuations coexist, we have obtained a phase diagram against the off-site repulsion V and band filling n for the extended, repulsive Hubbard model on the square lattice with the fluctuation exchange approximation. We have found the existence of (i) a transition between dxy and d x 2 −y 2 pairing symmetries, (ii) f -pairing in between the d x 2 −y 2 and CDW phases for intermediate 0.5 < n < 1.0 and large V , and (iii) for anisotropic cases the pairing symmetry changing, in agreement with a previously proposed "generic phase diagram", as d → f → s when V (hence the charge fluctuations) are increased. All these are consequences of the structure in the charge and spin susceptibilities, which have peaks habitating at common or segregated positions in k space.

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Spin-fluctuation exchange study of superconductivity in two- and three-dimensional single-band Hubbard models

Abstract: In order to identify the most favorable situation for superconductivity in

Cited by 82 publications

References 34 publications

Quantum Monte Carlo study of the pairing symmetry competition in the Hubbard model

Quantum Monte Carlo study of the pairing symmetry competition in the Hubbard model

Migdal’s theorem and the pseudogap

Phase diagram of the two-dimensional extended Hubbard model: Phase transitions between different pairing symmetries when charge and spin fluctuations coexist

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