Impurity effects in
                    <i>p</i>
                    -wave superconductors

Maki, Kazumi; Puchkaryov, E.

doi:10.1209/epl/i2000-00302-7

Cited by 13 publications

(18 citation statements)

References 28 publications

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“…This is consistent with the well-known universal thermal transport [29][30][31] of a superconducting state with line nodes; while it is completely different from what is expected for the isotropic chiral p-wave case. For isotropic chiral p-wave, the residual thermal conductivity becomes vanishingly small 33,34 in the zero impurity scattering limit, since the number of low energy excitations available for heat transport decreases rapidly below the isotropic superconducting gap and impurity induced sub-gap states are localized 35 .…”

Section: Introductionmentioning

confidence: 99%

Effects of deep superconducting gap minima and disorder on residual thermal transport in Sr2RuO4

2018

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Recent thermal conductivity measurements on Sr2RuO4 [E. Hassinger et al., Phys. Rev. X 7, 011032 (2017)] were interpreted as favoring a pairing gap function with vertical line nodes while conflicting with chiral p-wave pairing. Motivated by this work we study the effects of deep superconducting gap minima on impurity induced quasiparticle thermal transport in chiral p-wave models of Sr2RuO4. Combining a self-consistent T-matrix analysis and self-consistent Bogoliubovde-Gennes calculations, we show that the dependence of the residual thermal conductivity on the normal state impurity scattering rate can be quite similar to the d-wave pairing state that was shown to fit the thermal conductivity measurements, provided the normal state impurity scattering rate is large compared with the deep gap minima. Consequently, thermal conductivity measurements on Sr2RuO4 can be reconciled with a chiral p-wave pairing state with deep gap minima. However, the data impose serious constraints on such models and these constraints are examined in the context of several different chiral p-wave models.arXiv:1810.00932v2 [cond-mat.supr-con]

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Section: Introductionmentioning

confidence: 99%

Effects of deep superconducting gap minima and disorder on residual thermal transport in Sr2RuO4

2018

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“…Moreover, κ 00 /T values converge to a finite value of 1.7 ±0.15 W/K 2 m in thehΓ /k B T c0 → 0 limit, giving strong evidence for the nodal gap structure. The finite κ 00 /T should appear even in the superconductors with fully gapped non-s-wave state (e.g., isotropic 2D p-wave state [20]) when a small number of impurities exist, but it should vanish in the Γ → 0 limit with breaking of the universality [39].…”

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confidence: 99%

Universal Heat Transport inSr2RuO4

et al. 2002

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We present the temperature dependence of the thermal conductivity κ(T ) of the unconventional superconductor Sr2RuO4 down to low temperatures (∼100 mK). In T → 0 K limit we found a finite residual term in κ/T , providing clear evidence for the superconducting state with an unconventional pairing. The residual term remains unchanged for samples with different Tc, demonstrating the universal character of heat transport in this spin-triplet superconductor. The low-temperature behavior of κ suggests the strong impurity scattering with a phase shift close to π/2. A criterion for the observation of universality is experimentally deduced.PACS numbers: 74.20. Rp, 74.25.Fy, 74.70.Pq Through the study of the cuprate superconductor in the last decade, a notable progress has been made in an understanding of the thermodynamic and transport properties of quasi-particles (QP) in unconventional superconductors. One of the important findings is the novel phenomenon called the universal transport, pointed out first by Lee [1]. In an unconventional superconductor with nodes in the superconducting (SC) gap, nonmagnetic impurities suppress the transition temperature (T c ) and induce the finite density of QP states at the Fermi level with the energy width γ imp [2]. The presence of impurities increases both the QP density and the impurity scattering rate, which completely cancel each other [3,4]. In this case the QP transport, such as thermal conductivity (κ), restores the temperature (T ) dependence typical for the normal state (e.g. κ ∝ T ) [5] and becomes independent of impurity concentration. The magnitude of the residual term in κ/T depends only on the QP spectrum near the gap nodes, providing a useful tool for studying the SC order parameter [4].Experimentally, the universal residual term in κ/T at T → 0 K has been reported in optimally-doped high-T c cuprates YBa 2 Cu 3 O 6.9 [6] and Bi 2 Sr 2 CaCu 2 O 8 [7,8].Their residual values are consistent with the d-wave SC gap structure [9]. For non-d-wave gap symmetries, the universal conductivity has never been observed. In contrast, the extrapolated κ/T at T → 0 K of the spin-triplet superconductor UPt 3 [10,11] rapidly increases with the density of defects, showing no universal behavior, and the residual term seems to vanish in zero-disorder limit [11]. The origin of the lack of universality is still unclear, similar to the case of under-doped cuprates [12], and it is strongly desirable to extend studies to other unconventional superconductors.In this respect, of special interest is the study of Sr 2 RuO 4 , a unique quasi-two-dimensional (Q2D) spin triplet superconductor [13,14]. This material has a layered perovskite structure [15] and its electronic state is well described in the Landau-Fermi liquid model [16]. The SC state of Sr 2 RuO 4 (T c = 1.5 K) is chiral with a broken time reversal symmetry [17] and its T c is rapidly suppressed by non-magnetic impurities [18,19]. Views on the SC gap symmetry of Sr 2 RuO 4 changed in time. Early theoretical prediction of the fully ga...

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“…While the BCS s-wave pairing state is robust against nonmagnetic impurities [1], unconventional pairing states with other symmetries are usually rather fragile [2][3][4][5][6][7]. The impurity scatterings modify transport and thermodynamic properties of unconventional superconductors, which have a crucial impact on the identification of the pairing symmetry, e.g., in p-wave superconductors [8][9][10]. Specifically, the tunneling spectroscopy is an important experimental tool to identify an unconventional superconductor.…”

Section: Introductionmentioning

confidence: 99%

Influence of the impurity scattering on charge transport in unconventional superconductor junctions

Burset

Tanuma

et al. 2016

Phys. Rev. B

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We study the influence of nonmagnetic impurity scatterings on the tunneling conductance of a junction consisting of a normal metal and a disordered unconventional superconductor by solving the quasiclassical Eilenberger equation self-consistently. We find that the impurity scatterings in both the Born and the unitary limits affect the formation of the Andreev bound states and modify strongly the tunneling spectra around zero bias. Our results are interpreted well by the appearance of odd-frequency Cooper pairs near the interface and by the divergent behavior of the impurity self-energy. The present paper provides a useful tool to identify the pairing symmetry of unconventional superconductors in experiments.

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Impurity effects in p -wave superconductors

Cited by 13 publications

References 28 publications

Effects of deep superconducting gap minima and disorder on residual thermal transport in Sr2RuO4

Effects of deep superconducting gap minima and disorder on residual thermal transport in Sr2RuO4

Universal Heat Transport inSr2RuO4

Influence of the impurity scattering on charge transport in unconventional superconductor junctions

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