Correlation-driven<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>d</mml:mi></mml:math>-wave superconductivity in Anderson lattice model: Two gaps

Wysokiński, Marcin; Kaczmarczyk, Jan; Spałek, J.

doi:10.1103/physrevb.94.024517

Cited by 25 publications

(28 citation statements)

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“…To account for nonlocal spatial correlations in finite dimensions, higher orders of the expansion (k > 0) are systematically incorporated in Eq. (4) and expectation values of the products of the operators are evaluated diagrammatically [25,26,[42][43][44][45][46][47]. By construction [25], the convergence of the sum with respect to k is reached relatively quickly, and here we found that k = 4 is already satisfying (see the Supplemental Material [48]).…”

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confidence: 81%

Many-body breakdown of indirect gap in topological Kondo insulators

Wysokiński

Fabrizio

2016

Phys. Rev. B

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We show that the inclusion of nonlocal correlation effects in a variational wave function for the ground state of a topological Anderson lattice Hamiltonian is capable of describing both topologically trivial insulating phases and nontrivial ones characterized by an indirect gap, as well as its closure at the transition into a metallic phase. The method, though applied to an oversimplified model, thus captures the metallic and insulating states that are indeed observed in a variety of Kondo semiconductors, while accounting for topologically nontrivial band structures. PACS numbers: 71.27.+a, 71.30.+h, 03.65.Vf Introduction. Phenomena at the crossroads of topological insulators and strongly correlated systems have recently gained a lot of attention, mainly stimulated by theoretical proposals that the inclusion of strong correlations in specific models with a nontrivial topological content may give rise to novel and interesting phenomena [1][2][3][4][5]. However, electronic correlations in most of the discovered topological insulators [6,7] seem to be relatively weak, and hence of minor importance. For that reason, the concept of topological Kondo insulators (TKIs) originally put forward in Refs.[8] and [9] is particularly appealing due to its possible realization in already known Kondo insulating compounds [10]. Notably, SmB 6 is convincingly confirmed to be a TKI [11][12][13][14][15][16][17][18][19] with strong evidence of the essential role played by many-body correlations [20,21].Theoretically, the main physical properties of TKI are frequently described in the framework of topological Anderson lattice models in which strong spin-orbit coupling is encoded into a spin-dependent hybridization with odd parity in momentum space [8,9,22]. Many-body correlations in these models have been mostly treated by the slave-boson approach or by the dynamical mean-field theory (DMFT), and predicted to induce quantum phase transitions between topologically distinct bulk insulating phases [22][23][24].The aim of this work is to demonstrate that accounting for nonlocal spatial correlations, beyond those already well captured by the mentioned techniques, plays an important role in modeling TKIs. Specifically, those nonlocal correlations supply the f electron self-energy with a momentum dependence, which is otherwise purely local within DMFT and at the saddle point of the slave-boson theory. Remarkably, such a momentum dependence allows one to describe, above a critical interaction strength, the emergence of a topological Kondo insulator with an indirect gap, and its subsequent closure at the transition into a metallic state, an intriguing result opposite to the conventional Mott phenomenon where increasing interaction instead favours the onset of an insulating state. We disclose this scenario in two dimensions by means of the diagrammatic expansion of the Gutzwiller wave function (GWF) technique [25,26]. CeIrSb [35]). Moreover, assuming that increasing pressure roughly corresponds to reducing the interaction strength, we can ...

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confidence: 81%

Many-body breakdown of indirect gap in topological Kondo insulators

Wysokiński

Fabrizio

2016

Phys. Rev. B

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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.…”

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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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“…(2), is a complex many-body problem and may be carried out for finite systems by variational Monte-Carlo methods (see., e.g., [22]) or in thermodynamic limit by suitable diagrammatic-expansion. [23][24][25] Within the latter framework, eliminating Hartree-bubbles improves substantially series convergence and is achieved by imposing an additional constraint 23,26P 2…”

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confidence: 99%

Coexistent spin-triplet superconducting and ferromagnetic phases induced by Hund's rule coupling and electronic correlations: Effect of the applied magnetic field

et al. 2019

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Recently proposed local-correlation-driven pairing mechanism, describing ferromagnetic phases (FM1 and FM2) coexisting with spin-triplet superconductivity (SC) within a single orbitally degenerate Anderson lattice model, is extended to the situation with applied Zeeman field. The model provides and rationalizes in a semiquantitative manner the principal features of the phase diagram observed for UGe2 in the field absence [cf. Phys. Rev. B 97, 224519 (2018)]. As spin-dependent effects play a crucial role for both the ferromagnetic and SC states, the role of the Zeeman field is to single out different stable spin-triplet SC phases. This analysis should thus be helpful in testing the proposed real-space pairing mechanism, which may be regarded as complementary to spin-fluctuation theory suitable for 3 He. Specifically, we demonstrate that the presence of the two distinct phases, FM1 and FM2, and associated field-driven metamagnetic transition between them, induce respective metasuperconducting phase transformation. At the end, we discuss briefly how the spin fluctuations might be incorporated as a next step into the considered here renormalized quasiparticle picture. arXiv:1902.08444v2 [cond-mat.str-el]

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

Cited by 25 publications

References 64 publications

Many-body breakdown of indirect gap in topological Kondo insulators

Many-body breakdown of indirect gap in topological Kondo insulators

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

Coexistent spin-triplet superconducting and ferromagnetic phases induced by Hund's rule coupling and electronic correlations: Effect of the applied magnetic field

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