Formation of Cooper pairs between conduction and localized electrons in heavy-fermion superconductors

Masuda, Keisuke; Yamamoto, Daisuke

doi:10.1103/physrevb.87.014516

Cited by 9 publications

(14 citation statements)

References 45 publications

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“…By the same token, one expects the Kondo-like term to contribute to inter-orbital pairing (e.g. c † f † [43]), which plays an important role in unconventional superconductivity [44,45] in the context of heavy fermion materials, such as CeCoIn 5 [23,25,43,46,47]. However, here we are dealing with well localised magnetism, such as Tm, Er and Ho-based materials, so that the contribution from unconventional channels may be disregarded in a first approach.…”

Section: Model and Methodsmentioning

confidence: 99%

A mean-field approach to Kondo-attractive-Hubbard model

Costa

Lima

Paiva

et al. 2018

J. Phys.: Condens. Matter

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With the purpose of investigating coexistence between magnetic order and superconductivity, we consider a model in which conduction electrons interact with each other, via an attractive Hubbard on-site coupling U, and with local moments on every site, via a Kondo-like coupling, J. The model is solved on a simple cubic lattice through a Hartree-Fock approximation, within a 'semi-classical' framework which allows spiral magnetic modes to be stabilized. For a fixed electronic density, n , the small J region of the ground state (T = 0) phase diagram displays spiral antiferromagnetic (SAFM) states for small U. Upon increasing U, a state with coexistence between superconductivity (SC) and SAFM sets in; further increase in U turns the spiral mode into a Néel antiferromagnet. The large J region is a (singlet) Kondo phase. At finite temperatures, and in the region of coexistence, thermal fluctuations suppress the different ordered phases in succession: the SAFM phase at lower temperatures and SC at higher temperatures; also, reentrant behaviour is found to be induced by temperature. Our results provide a qualitative description of the competition between local moment magnetism and superconductivity in the borocarbides family.

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Section: Model and Methodsmentioning

confidence: 99%

A mean-field approach to Kondo-attractive-Hubbard model

Costa

Lima

Paiva

et al. 2018

J. Phys.: Condens. Matter

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“…Inter-band pairing gives rise to ground states with finite q-pairing states but also to anisotropic s-wave superconductivity [23]. The main difference concerning the effect of hybridization for intra-band and inter-band pairing is that in the latter case hybridization favors superconductivity [23] while for intra-band pairing it is mostly deleterious.…”

Section: The Modelmentioning

confidence: 99%

“…We have neglected an inter-band attractive interaction among the c and f -electrons, and an intra-band term between the c-electrons. Also we did not include [22] an inter-band pair hopping term which arises in second order in the hybridization when applying a Schrieffer-Wolf transformation for the Anderson lattice model [23]. Inter-band pairing gives rise to ground states with finite q-pairing states but also to anisotropic s-wave superconductivity [23].…”

Section: The Modelmentioning

confidence: 99%

“…Also we did not include [22] an inter-band pair hopping term which arises in second order in the hybridization when applying a Schrieffer-Wolf transformation for the Anderson lattice model [23]. Inter-band pairing gives rise to ground states with finite q-pairing states but also to anisotropic s-wave superconductivity [23]. The main difference concerning the effect of hybridization for intra-band and inter-band pairing is that in the latter case hybridization favors superconductivity [23] while for intra-band pairing it is mostly deleterious.…”

Section: The Modelmentioning

confidence: 99%

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s- and d-wave superconductivity in a two-band model

et al. 2016

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Superconductivity in strongly correlated systems is a remarkable phenomenon that attracts a huge interest. The study of this problem is relevant for materials as the high T c oxides, pnictides and heavy fermions. In this work we study a realistic model that includes the relevant physics of superconductivity in the presence of strong Coulomb correlations. We consider a two-band model, since most of these correlated systems have electrons from at least two different atomic orbitals coexisting at their Fermi surface. The Coulomb repulsion is taken into account through a local repulsive interaction. Pairing is considered among quasiparticles in neighbouring sites and we allow for different symmetries of the order parameter. In order to deal with the strong local correlations, we use the well known slave boson approach that has proved very successful for this problem. Here we are interested in obtaining the zero temperature properties of the model, specifically its phase diagram and the existence and nature of superconducting quantum critical points. We show that these can arise by increasing the mixing between the two bands. Since this can be controlled by external pressure or doping, our results have a direct relation with experiments. We show that the superconductor-to-normal transition can be either to a metal, a correlated metal or to an insulator. Also we compare the relative stability of s and d-wave paired states for different regions of parameter space and investigate the BCS-BEC crossover in the two-band lattice model as function of the strength of the pairing interaction.

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“…[12][13][14][15]). Previous considerations of pairing in HFS of a purely electronic origin have involved related models such as the Kondo lattice model [16][17][18][19], the Anderson-Kondo lattice model [20][21][22][23] or ALM with the Falicov-Kimball term, the presence of which enhances the valence-fluctuation-induced pairing [9]. Also, there exists a variational approach to the intrinsic SC pairing in ALM [24], with the s-wave character of SC gap.…”

mentioning

confidence: 99%

Correlation-drivend-wave superconductivity in Anderson lattice model: Two gaps

2016

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We present the full Gutzwiller-wave-function solution of the Anderson lattice model in two dimensions that leads to the correlation-driven multigap superconducting (SC) ground state with the dominant d x 2 −y 2 -wave symmetry. The results are consistent with the principal properties of the heavy-fermion superconductor CeCoIn5. We regard the pairing mechanism as universal and thus applicable to other Ce-based heavy-fermion compounds. Additionally, a gain in kinetic energy in the SC state takes place, as is also the case for high-temperature superconductors.

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Formation of Cooper pairs between conduction and localized electrons in heavy-fermion superconductors

Cited by 9 publications

References 45 publications

A mean-field approach to Kondo-attractive-Hubbard model

A mean-field approach to Kondo-attractive-Hubbard model

s- and d-wave superconductivity in a two-band model

Correlation-drivend-wave superconductivity in Anderson lattice model: Two gaps

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