Superconducting state with a finite-momentum pairing mechanism in zero external magnetic field

Loder, Florian; Kampf, Arno P.; Kopp, Thilo

doi:10.1103/physrevb.81.020511

Cited by 57 publications

(88 citation statements)

References 16 publications

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“…A BCS-mean-field-theory of a extended Hubbard model in two dimensions has been developed by Loder and coworkers 21,22 who found that, as part of a rich phase diagram, the PDW is the ground state for large enough interactions. Earlier mean field theory results in the t−J model by Yang et al 23 found that the PDW is energetically very close to being the ground state.…”

Section: Introductionmentioning

confidence: 99%

Pair-density-wave superconducting order in two-leg ladders

Jaefari

Fradkin

2012

Phys. Rev. B

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We show using bosonization methods that extended Hubbard-Heisenberg models on two types of two leg ladders (without flux and with flux π per plaquette) have commensurate pair-density wave (PDW) phases. In the case of the conventional (flux-less) ladder the PDW arises when certain filling fractions for which commensurability conditions are met. For the flux π ladder the PDW phase is generally present. The PDW phase is characterized by a finite spin gap and a superconducting order parameter with a finite (commensurate in this case) wave vector and power-law superconducting correlations. In this phase the uniform superconducting order parameter, the 2kF charge-densitywave (CDW) order parameter and the spin-density-wave Néel order parameter exhibit short range (exponentially decaying) correlations. We discuss in detail the case in which the bonding band of the ladder is half filled for which the PDW phase appears even at weak coupling. The PDW phase is shown to be dual to a uniform superconducting (SC) phase with quasi long range order. By making use of bosonization and the renormalization group we determine the phase diagram of the spin-gapped regime and study the quantum phase transition. The phase boundary between PDW and the uniform SC ordered phases is found to be in the Ising universality class. We generalize the analysis to the case of other commensurate fillings of the bonding band, where we find higher order commensurate PDW states for which we determine the form of the effective bosonized field theory and discuss the phase diagram. We compare our results with recent findings in the KondoHeisenberg chain. We show that the formation of PDW order in the ladder embodies the notion of intertwined orders.

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Section: Introductionmentioning

confidence: 99%

Pair-density-wave superconducting order in two-leg ladders

Jaefari

Fradkin

2012

Phys. Rev. B

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“…Based on a microscopic model, it was shown in reference [33] that a PDW state cannot result from an on-site pairing interaction. However, the PDW state can be a stable alternative for unconventional superconductors with gap nodes, specifically for d-wave superconductivity as realized in the high-T c cuprate superconductors.…”

Section: Resultsmentioning

confidence: 99%

“…Nevertheless it is still assumed that pairing occurs only for one specific angular momentum q. For conventional superconductors, this assumption is generally true, although for superconductors with gap nodes, the situation may be different, as was shown for d-wave pairing symmetry in reference [33]. In this section, we use the 1 In the literature the symmetric…”

Section: Superconducting State: Emergence Of a New Periodicitymentioning

confidence: 99%

Flux-Periodicity Crossover from hc/e in Normal Metallic to hc/2e in Superconducting Loops

Loder¹,

Kampf²,

Kopp³

2012

Superconductors - Materials, Properties and Applications

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The periodic response of a metallic or a superconducting ring to an external magnetic flux is one of the most evident manifestations of quantum mechanics. It is generally understood that the oscillation period hc/2e in the superconducting state is half the period hc/e in the metallic state, because the supercurrent is carried by Cooper pairs with a charge 2e. On the basis of the Bardeen-Cooper-Schrieffer theory we discuss, in which cases this simple interpretation is valid and when a more careful analysis is needed. In fact, the knowledge of the oscillation period of the current in the ring provides information on the electron interactions. In particular, we analyze the crossover from the hc/e periodic normal current to the hc/2e periodic supercurrent upon turning on a pairing interaction in a metal ring. Further, we elaborate on the periodicity crossover when cooling a metallic loop through the superconducting transition temperature Tc.

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“…16 In a series of papers, Loder and collaborators 17,18 found that a PDW superconducting state is preferred in a tight-binding model with strong attractive interactions (although the critical value of the coupling constant above which the PDW is stable is presumably outside the range of validity of the weak coupling theory). Similarly, PDW states with broken time-reversal invariance and parity have been found recently 19,20 in a 'hot spot' model, which also requires a critical (and typically not small) value of a coupling constant.…”

Section: -11mentioning

confidence: 99%

“…(4.2)) has pockets of Bogoliubov quasiparticles, as it is also found in the weak coupling theories. 4,14,17,44,50,51 The size of the pockets depends on the strength of the SC gap. In addition, we compute the spectral function given by (see for instance Ref.…”

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confidence: 99%

Quasi-one-dimensional pair density wave superconducting state

2015

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We provide a quasi-one-dimensional model which can support a pair-density-wave (PDW) state, in which the superconducting (SC) order parameter modulates periodically in space, with gapless Bogoliubov quasiparticle excitations. The model consists of an array of strongly-interacting one-dimensional systems, where the one-dimensional systems are coupled to each other by local interactions and tunneling of the electrons and Cooper pairs between them. Within the interchain mean-field theory, we find several SC states from the model, including a conventional uniform SC state, PDW SC state, and a coexisting phase of the uniform SC and PDW states. In this quasi-1D regime we can treat the strong correlation physics essentially exactly using bosonization methods and the crossover to the 2D system by means of interchain mean field theory. The resulting critical temperatures of the SC phases generically exhibit a power-law scaling with the coupling constants of the array, instead of the essential singularity found in weak-coupling BCS-type theories. Electronic excitations with an open Fermi surface, which emerge from the electronic Luttinger liquid systems below their crossover temperature to the Fermi liquid, are then coupled to the SC order parameters via the proximity effect. From the Fermi surface thus coupled to the SC order parameters, we calculate the quasiparticle spectrum in detail. We show that the quasiparticle spectrum can be fully gapped or nodal in the uniform SC phase and also in the coexisting phase of the uniform SC and PDW parameters. In the pure PDW state, the excitation spectrum has a reconstructed Fermi surface in the form of Fermi pockets of Bogoliubov quasiparticles.

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Superconducting state with a finite-momentum pairing mechanism in zero external magnetic field

Cited by 57 publications

References 16 publications

Pair-density-wave superconducting order in two-leg ladders

Pair-density-wave superconducting order in two-leg ladders

Flux-Periodicity Crossover from hc/e in Normal Metallic to hc/2e in Superconducting Loops

Quasi-one-dimensional pair density wave superconducting state

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