Anisotropic Superconducting Gap in the Spin-Triplet Superconductor<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>Sr</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>RuO</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>: Evidence from a Ru-NQR Study

Ishida, K.; Mukuda, H.; Kitaoka, Y.; Mao, Zhiqiang; Mori, Y.; Maeno, Y.

doi:10.1103/physrevlett.84.5387

Cited by 169 publications

(144 citation statements)

References 23 publications

Supporting

Mentioning

130

Contrasting

Order By: Relevance

“…These experiments initially led to suggestion of the 2D chiral (time-reversal non-invariant), isotropic, nodeless p-wave pairing potential [8]. However, the power-law temperature dependences found in specific heat [9], nuclear relaxation rate [10], penetration depth [11], thermal conductivity [12], and ultrasonic attenuation [13,14] indicate nodes in the energy gap. In response to these experiments, the following alternative order parameters were proposed [15]: anisotropic p-wave [16], p-wave with horizontal lines of nodes [17], and fwaves with vertical [17,18] or horizontal lines of nodes [19].…”

Section: Introductionmentioning

confidence: 99%

Edge states and determination of pairing symmetry in superconductingSr2RuO4

2002

View full text Add to dashboard Cite

We calculate the energy dispersion of the surface Andreev states and their contribution to tunneling conductance for the order parameters with horizontal and vertical lines of nodes proposed for superconducting Sr2RuO4. For vertical lines, we find double peaks in tunneling spectra reflecting the van Hove singularities in the density of surface states originating from the turning points in their energy dispersion. For horizontal lines, we find a single cusp-like peak at zero bias, which agrees very well with the experimental data on tunneling in Sr2RuO4.

show abstract

Section: Introductionmentioning

confidence: 99%

Edge states and determination of pairing symmetry in superconductingSr2RuO4

2002

View full text Add to dashboard Cite

show abstract

“…Views on the SC gap symmetry of Sr 2 RuO 4 changed in time. Early theoretical prediction of the fully gapped p-wave chiral state [20] did not find support in recent experiments, suggesting the SC gap with line nodes [21][22][23][24], likely running parallel to the conducting plane [25][26][27]. Several new theoretical models have been proposed [28][29][30][31] to explain the experimentally observed "triplet-chiral-nodal" SC order parameter.…”

mentioning

confidence: 99%

Universal Heat Transport inSr2RuO4

et al. 2002

Self Cite

View full text Add to dashboard Cite

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...

show abstract

“…Bechgaard salts [8], ruthenates [4], and heavy fermion materials [9] showed 1=T 1 T 3 at low temperatures and for small magnetic fields. Such behavior has usually been interpreted as a signature of nodes in the quasiparticle gap on the Fermi surface.…”

mentioning

confidence: 99%

“…NMR analysis has been successfully applied to study magnetic insulators (see, e.g., [1], and references therein) as well as several classes of unconventional superconductors, including high T c cuprates [2], heavy fermion materials [3], ruthenates [4], and organic superconductors [5]. In particular, NMR experiments have been useful for analyzing the symmetry of the superconducting order parameter [6] and for clarifying the structure of the phase diagram in systems with competing orders [7].…”

mentioning

confidence: 99%

Spin-Wave Contribution to the Nuclear Spin-Lattice Relaxation in Triplet Superconductors

Rostunov

Demler²,

Georges³

2006

Phys. Rev. Lett.

View full text Add to dashboard Cite

We discuss collective spin-wave excitations in triplet superconductors with an easy axis anisotropy for the order parameter. Using a microscopic model for interacting electrons, we estimate the frequency of such excitations in Bechgaard salts and ruthenate superconductors to be 1 and 20 GHz, respectively. We introduce an effective bosonic model to describe spin-wave excitations and calculate their contribution to the nuclear spin-lattice relaxation rate. We find that, in the experimentally relevant regime of temperatures, this mechanism leads to the power law scaling of 1=T 1 with temperature. For two-and threedimensional systems, the scaling exponents are 3 and 5, respectively. We discuss experimental manifestations of the spin-wave mechanism of the nuclear spin-lattice relaxation.

show abstract

Anisotropic Superconducting Gap in the Spin-Triplet SuperconductorSr2RuO4: Evidence from a Ru-NQR Study

Cited by 169 publications

References 23 publications

Edge states and determination of pairing symmetry in superconductingSr2RuO4

Edge states and determination of pairing symmetry in superconductingSr2RuO4

Universal Heat Transport inSr2RuO4

Spin-Wave Contribution to the Nuclear Spin-Lattice Relaxation in Triplet Superconductors

Contact Info

Product

Resources

About