Superconductivity in the Anderson lattice: a finite-<i>U</i>slave boson description

Sacramento, P. D.; Aparicio, Juan Pablo; Nunes, Guilherme S.

doi:10.1088/0953-8984/22/6/065702

Cited by 9 publications

(17 citation statements)

References 37 publications

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“…For instance, for n ≈ 0.5, as well as n ≈ 3.5 and even symmetry of hybridization, two superconducting regions are obtained: one with the usual initial decrease of the superconducting critical temperature with V and a second with a dome for higher values of hybridization. The Coulomb repulsion is also an important ingredient affecting superconductivity: for certain values of band-filling it can lead to a suppression of the superconducting phase, instead of a continuous asymptotic decrease as reported in previous works 8,20 .…”

Section: Discussionmentioning

confidence: 56%

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Influence of the symmetry of hybridization on the critical temperature of multiband superconductors

et al. 2019

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In this work we study a two-band model of a superconductor in a square lattice. One band is narrow in energy and includes local Coulomb correlations between its quasi-particles. Pairing occurs in this band due to nearest neighbor attractive interactions. Extended s-wave, as well as d-wave symmetries of the superconducting order parameter are considered. The correlated electrons hybridize with those in another, wide conduction band through a k-dependent mixing, with even or odd parity depending on the nature of the orbitals. The many-body problem is treated within a slave-boson approach that has proved adequate to deal with the strong electronic correlations that are assumed here. Since applied pressure changes mostly the ratio between hybridization and bandwidths, we can use this ratio as a control parameter to obtain the phase diagrams of the model. We find that for a wide range of parameters, the critical temperature increases as a function of hybridization (pressure), with a region of first-order transitions. When frustration is introduced it gives rise to a stable superconducting phase. We find that superconductivity can be suppressed for specific values of band-filling due to the Coulomb repulsion. We show how pressure, composition and strength of correlations affect the superconductivity for different symmetries of the order parameter and the hybridization. arXiv:1904.04945v1 [cond-mat.supr-con]

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Section: Discussionmentioning

confidence: 56%

“…and where the square root term ensures that the mapping becomes trivial at the mean-field level in the non-interacting limit (U → 0). The usual procedure consists in taking a mean-field approach where we assume the slave bosons to be condensed 8,20,32 . Then all bosons operators are replaced by their expectation values as,…”

Section: The Modelmentioning

confidence: 99%

Influence of the symmetry of hybridization on the critical temperature of multiband superconductors

et al. 2019

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“…(1) shows the BCS-BEC crossover from the analysis of the order parameter amplitude and the chemical potential, as functions of the density of particles (not shown). It is worth also to point out that superconductivity can be enhanced by a small momentum-independent hybridization, as in heavy-fermions systems with large local Coulomb repulsion, or even with U ¼ 1, as shown, for example, using the slave boson formalism [24]. Since hybridization can be tuned by external parameters, increasingλ, by pressure or doping provides a mechanism not only for increasing the critical temperatures in d-wave superconductors but also to drive the BCS-BEC crossover.…”

Section: Enhancement Of Critical Temperature With a Non-symmetrical Hmentioning

confidence: 98%

Enhancement of the critical temperature of d-wave superconductors by odd-parity electronic mixing

Reyes

Continentino

2015

Solid State Communications

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“…This one-body mixing term can be tuned by external parameters such as pressure permitting the exploration of the phase diagram and quantum phase transitions of the model. The last term explicitly describes an effective attraction between f -electrons in neighboring sites (J ij > 0), which is responsible for superconductivity [9]. Notice that this term also describes antiferromagnetic (AF), xy-type, exchange interactions between these electrons, such that, magnetic and superconducting ground states are in competition.…”

Section: The Modelmentioning

confidence: 99%

“…The Anderson lattice model (ALM) is generally accepted as an appropriate model for describing both magnetic and superconducting instabilities [8,9,10,11,12] in strongly correlated multi-band systems. Many studies have shown that the pairing between the nearly localized d of f -electrons is the responsible for the appearance of superconductivity [13,14].…”

Section: Introductionmentioning

confidence: 99%

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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Superconductivity in the Anderson lattice: a finite-Uslave boson description

Cited by 9 publications

References 37 publications

Influence of the symmetry of hybridization on the critical temperature of multiband superconductors

Influence of the symmetry of hybridization on the critical temperature of multiband superconductors

Enhancement of the critical temperature of d-wave superconductors by odd-parity electronic mixing

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

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