Mean-field approach to unconventional superconductivity

Mauger, A.; Noat, Yves

doi:10.1016/j.physc.2014.04.041

Physica C: Superconductivity and its Applications

2014

DOI: 10.1016/j.physc.2014.04.041

|View full text |Cite

Mean-field approach to unconventional superconductivity

A. Mauger¹,

Yves Noat²

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...

Citation Types

Supporting

Mentioning

Contrasting

Year Published

2015

2017

Publication Types

Select...

Article4

Relationship

Self Cite4

Independent0

Authors

Journals

Cited by 4 publications

(25 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First, precise fits to the QP tunneling spectra from Renner et al [37], as a function of T , allow to determine the parameters ∆ 0 and σ 0 , as well as the QP peak heights (PH). As we showed in our previous work [22,42], the attenuation of the DOS peak height, analogous to the effect shown in the spectra of Fig. 4, is due to the gradual decrease in the interaction β(T ), as expected from eq.…”

supporting

confidence: 83%

“…As in Refs. [22,41,42], these characteristics are found without a dynamical collective mode. It remains to be investigated whether similar features seen in the pnictide LiFeAs [44] have the same origin.…”

mentioning

confidence: 92%

“…The QP DOS is obtained directly from the spectral function using : N S (E) = 2 k A( k , E) where, for a dwave pairing symmetry, ∆ k (θ) = ∆ p cos(2θ) leading to the typical V-shaped DOS [40,57,58]. However, as we have shown repeatedly [22,41,42], such a d-wave DOS, with weak logarithmic singularities at the coherence peaks and no dip-hump structures, fails to match the experimental spectra.…”

mentioning

confidence: 99%

“…(25,26) accurately matches the wide peaks and characteristic dips as measured in the spectra, see Fig.4. The derivation of the DOS is given a full treatment in [41,42]. We recall that, neglecting Γ-broadening, it depends on the following derivative : (27) where N S (E, θ) is the partial DOS in the θ direction.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Pair–pair interactions as a mechanism for high-T_csuperconductivity

Mauger¹,

Noat²

2015

Supercond. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

-The mutual interaction between Cooper pairs is proposed as a mechanism for the superconducting state. Above Tc, pre-existing but fluctuating Cooper pairs give rise to the unconventional pseudogap (PG) state, well-characterized by experiment. At the critical temperature, the pair-pair interaction induces a Bose-like condensation of these preformed pairs leading to the superconducting (SC) state. Below Tc, both the condensation energy and the pair-pair interaction β are proportional to the condensate density Noc(T ), whereas the usual Fermi-level spectral gap ∆p is independent of temperature. The new order parameter β(T ), can be followed as a function of temperature, carrier concentration and disorder -i.e. the phase diagrams. The complexity of the cuprates, revealed by the large number of parameters, is a consequence of the coupling of quasiparticles to Cooper-pair excitations. The latter interpretation is strongly supported by the observed quasiparticle spectral function. I. Introduction. -As Occam's razor would suggest, second order phase transitions often depend on few parameters [1]. Such is the case for the familiar magnetic, spin glass, charge-density wave, structural transitions, etc., and the more exotic Kosterlitz-Thouless case for two-dimensional systems [2]. The superconducting phase of 'classical' materials follows this trend wherein a weak attractive electron-electron interaction is responsible for the transition. Essentially a single energy scale, the SC gap parameter ∆ 0 at zero temperature, is relevant [3]. In the conventional theory of Bardeen, Cooper, Schrieffer (BCS) [3] pair-breaking quasiparticle excitations restore the normal-metal state at the transition, such that ∆ 0 = 1.76 k B T c . Moreover, ∆ 0 fixes the scale of the critical currents, for example in a Josephson junction, the upper critical field and the coherence length, such as the vortex core radius.

show abstract

supporting

confidence: 83%

mentioning

confidence: 92%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Pair–pair interactions as a mechanism for high-T_csuperconductivity

Mauger¹,

Noat²

2015

Supercond. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…In the continuum limit the spectral function A P G (k, E) acquires a significant width [22] and the T = 0 DOS becomes a convolution :…”

mentioning

confidence: 99%

From Cooper-pair glass to unconventional superconductivity: a unified approach to cuprates and pnictides

Mauger¹,

Noat²

2017

Solid State Communications

Self Cite

View full text Add to dashboard Cite

-We report a microscopic model wherein the unconventional superconductivity emerges from an incoherent 'Cooper-pair glass' state. Driven by the pair-pair interaction, a new type of quasi-Bose phase transition is at work. The interaction leads to the unconventional coupling of the quasiparticles to excited pair states, or 'super-quasiparticles', with a non-retarded energydependent gap. The model describes quantitatively the quasiparticle excitation spectra of both cuprates and pnictides, including the universal 'peak-dip-hump' signatures, and for the pseudogap phase above Tc. The results show that instantaneous pair-pair interactions account for the SC condensation without a collective mode.Despite its wide applications, the BCS theory [1] fails to account for the physical properties of a large variety of high-T c superconductors (SC), the cuprate family, but also the more recent iron-based superconductors. A striking feature of these materials is the proximity to an insulating phase, whether anti-ferromagnetic (cuprates), spin density wave (iron based SC, Bechgard salts) or localization (ultra-thin films). Just beyond the insulating phase, the SC dome appears in the phase diagram as a function of carrier concentration between two critical points. Understanding the transition from such an insulating to SC state is still a major challenge.Microscopic measurements reveal an unconventional quasiparticle (QP) dispersion, the 'peak-dip-hump' structure [2], often attributed to the coupling to a collective mode [3][4][5][6][7][8]. Although the peak to dip energy follows both the neutron resonance and T c as a function of doping [6,9,10], the finer shape of the QP spectra and their temperature dependence remain a challenge. Moreover, in the temperature range [T c , T * ] a pseudogap (PG) state persists, having a Fermi-level gap ∆ p much larger than the critical energy scale k B T c in cuprates (see [11] and ref. therein) and also in iron-based SC [12][13][14].In this letter, these questions are addressed within the pair-pair interaction model (PPI). We show that the main unconventional features of high-T c SC can be understood p-1 arXiv:1612.02268v2 [cond-mat.supr-con]

show abstract

Universal spectral signatures in pnictides and cuprates: the role of quasiparticle-pair coupling

Mauger

Noat

2017

J. Phys.: Condens. Matter

Self Cite

View full text Add to dashboard Cite

Understanding the physical properties of a large variety of high-T superconductors (SC), the cuprate family as well as the more recent iron-based superconductors, is still a major challenge. In particular, these materials exhibit the 'peak-dip-hump' structure in the quasiparticle density of states (DOS). The origin of this structure is explained within our pair-pair interaction (PPI) model: The non-superconducting state consists of incoherent pairs, a 'Cooper-pair glass' which, due to the PPI, undergoes a Bose-like condensation below T to the coherent SC state. We derive the equations of motion for the quasiparticle operators showing that the DOS 'peak-dip-hump' is caused by the coupling between quasiparticles and excited pair states, or 'super-quasiparticles'. The renormalized SC gap function becomes energy-dependent and non retarded, reproducing accurately the experimental spectra of both pnictides and cuprates, despite the large difference in gap value.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Mean-field approach to unconventional superconductivity

Cited by 4 publications

References 78 publications

Pair–pair interactions as a mechanism for high-T_csuperconductivity

Pair–pair interactions as a mechanism for high-T_csuperconductivity

From Cooper-pair glass to unconventional superconductivity: a unified approach to cuprates and pnictides

Universal spectral signatures in pnictides and cuprates: the role of quasiparticle-pair coupling

Contact Info

Product

Resources

About

Mean-field approach to unconventional superconductivity

Cited by 4 publications

References 78 publications

Pair–pair interactions as a mechanism for high-Tcsuperconductivity

Pair–pair interactions as a mechanism for high-Tcsuperconductivity

From Cooper-pair glass to unconventional superconductivity: a unified approach to cuprates and pnictides

Universal spectral signatures in pnictides and cuprates: the role of quasiparticle-pair coupling

Contact Info

Product

Resources

About

Pair–pair interactions as a mechanism for high-T_csuperconductivity

Pair–pair interactions as a mechanism for high-T_csuperconductivity