Excess current in superconducting<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">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 mathvariant="normal">RuO</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Laube, F.; Goll, G.; Eschrig, Matthias; Fogelström, Mikael; Werner, Ralph

doi:10.1103/physrevb.69.014516

Cited by 13 publications

(6 citation statements)

References 31 publications

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“…Phase-sensitive measurements based on the current-phase relation for Josephson junctions coupling a conventional s-wave superconductor, Au-In alloy, and Sr 2 RuO 4 support the interpretation that Sr 2 RuO 4 is an odd-parity superconductor [62]. Studies of the excess current obtained from point contact spectroscopy agree quantitatively with a p-wave triplet pairing state [63]. Evidence for broken time-reversal symmetry of the superconducting order parameter is provided by [64] and magneto-optical Kerr effect [65] experiments indicating that spontaneous currents and magnetic fields develop below T c in the Meissner state.…”

Section: Broken Time-inversion and Chiralitymentioning

confidence: 62%

Vortices in chiral, spin-triplet superconductors and superfluids

Sauls

Eschrig

2009

New J. Phys.

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Superconductors exhibit unconventional electronic and magnetic properties if the Cooper pair wave function breaks additional symmetries of the normal phase. Rotational symmetries in spin-and orbital spaces, as well as discrete symmetries such as space and time inversion, may be spontaneously broken. When this occurs in conjunction with broken global U(1) gauge symmetry, new physical phenomena are exhibited below the superconducting transition that are characteristic of the broken symmetries of the pair condensate. This is particularly true of vortices and related defects. Superconductors with a multi-component order parameter exhibit a variety of different vortex structures and closely related defects that are not possible in condensates belonging to a one-dimensional representation. In this article we discuss the structure of vortices in Fermionic superfluids and superconductors which break chiral symmetry, i.e. combined broken time-inversion and 2D parity. In particular, we consider the structure of vortices and defects that might be realized in thin films of 3 He-A and the layered superconductor Sr 2 RuO 4 , and identify some of the characteristic signatures of broken chiral symmetry that should be revealed by these defects.

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Section: Broken Time-inversion and Chiralitymentioning

confidence: 62%

Vortices in chiral, spin-triplet superconductors and superfluids

Sauls

Eschrig

2009

New J. Phys.

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“…10,[32][33][34][45][46][47][48][49] We follow the strategy outlined in Refs. [36][37][38]43,44 and use the quasiclassical theory to compute self-consistently the surface states of a dwave superconductor. The surface Green's function is then used to evaluate the conductance taking into account surface pair-breaking and hence a reduced order parameter at the surface.…”

Section: Symmetry Of the Superconducting Order Parametermentioning

confidence: 99%

Point-contact spectroscopy in heavy-fermion superconductors

et al. 2010

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We develop a microscopic model to calculate point-contact spectra between a metallic tip and a superconducting heavy-fermion system. We apply our tunneling model to the heavy fermion CeCoIn 5 , both in the normal and superconducting states. In point contact and scanning tunneling spectroscopy many heavy-fermion materials, such as CeCoIn 5 , exhibit an asymmetric differential conductance, dI / dV, combined with a strongly suppressed Andreev reflection signal in the superconducting state. We argue that both features may be explained in terms of a multichannel tunneling model in the presence of localized states near the interface. We find that it is not sufficient to tunnel into two itinerant bands of light and heavy electrons to explain the Fano line shape of the differential conductance. Localized states in the bulk or near the interface are an essential component for quantum interference to occur when an electron tunnels from the metallic tip of the point contact into the heavy-fermion system.

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“…White = zero, black = 0.01 (left) or 0.005 (right) states per unit cell. (e): BdG disorder averaged level spacing δs = En+1 − En ratio to first energy value E1 for n = 1 (solid) and n = 2 (dashed) as function of grain size L. (f): Evolution of the QC energy gapEg (black, ×) and ∆s on the surface (cyan, ) with magnetic field, B0 = Φ0/πξ0λ0 ≈ 2.2 T (derived assuming ξ0 = 2 nm, λ0 = 150 nm for YBCO) for a L = 40 ξ0 slab with surface disorder modeled by a thin layer (∼ 0.2ξ0) with a graded impurity concentration[25] and Tc,s = 0.065Tc.…”

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confidence: 99%

Model Evidence of a Superconducting State with a Full Energy Gap in Small Cuprate Islands

et al. 2013

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We investigate subdominant order parameters stabilizing at low temperatures in nanoscale high-T c cuprate islands, motivated by the recent observation of a fully gapped state in nanosized YBa 2 Cu 3 O 7À [D. Gustafsson et al., Nature Nanotech. 8, 25 (2013)]. Using complementary quasiclassical and tight-binding Bogoliubov-de Gennes methods, we show on distinctly different properties dependent on the symmetry being d x 2 Ày 2 þ is or d x 2 Ày 2 þ id xy . We find that a surface-induced d x 2 Ày 2 þ is phase creates a global spectroscopic gap which increases with an applied magnetic field, consistent with experimental observation. DOI: 10.1103/PhysRevLett.110.197001 PACS numbers: 74.78.Àw, 74.20.Rp, 74.50.+r, 74.72.Àh It is well established that high-temperature cuprate superconductors have a dominantly d x 2 Ày 2 -wave order parameter symmetry [1,2], but the existence of a subdominant symmetry has also long been considered. Of special interest are order parameters such as d x 2 Ày 2 þ id xy (d 1 þ id 2 ) and d 1 þ is, which fully gap the Fermi surface and break time-reversal (T ) symmetry [3][4][5][6]. Experimental data have been contradictory, invoking large imaginary subdominant orders to explain tunneling experiments in YBa 2 Cu 3 O 7À (YBCO) [7,8] and La 2Àx Sr x CuO 4 [9] or thermal conductivity in Bi 2 Sr 2 CaCu 2 O 8 [10] while, on the other hand, only very small imaginary components seem compatible with the absence of any measured spontaneous magnetization [2,[11][12][13][14].The possibility to find a T -symmetry breaking state is enhanced if the dominant d 1 -wave order parameter is locally reduced by, e.g., surface scattering. A nanoscale island of a curate superconductor is, by virtue of its large surface-to-area ratio, thus an ideal candidate to search for this elusive state. Very recently, a parity effect was reported in YBCO single-electron transistors (SETs), signalling a fully gapped low-temperature superconducting phase in nanoscale YBCO [15]. For a pure d 1 -wave superconductor there are always low-energy quasiparticle states available at the nodal points, into which the added charge in a SET can relax. Unless the nodal quasiparticles states are lifted by a spectroscopic energy gap E g , a parity effect should not be present in YBCO SETs. The experimental data show E g % 20-40 eV, making E g 3 orders of magnitude smaller than the gap Á d 1 % 20 meV in YBCO [15].The YBCO SETs studied in Ref.[15] have sizes of order 0:2 Â 0:2 Â 0:1 m 3 , making the energy-level spacing s of the nodal quasiparticles a candidate for the observed gap E g . While s $ 10 eV for an infinite mean-free path, surface disorder gives a reduced s $ 0:01 eV ( E g [16]. However, energy level spacing due to finite size is incompatible with the finite onset voltages of the SET current measured over a full gate charge period [17]. The measured E g is thus of superconducting origin and gaps the whole Fermi surface. Given the parent d 1 -wave order parameter of cuprates, finding E g demonstrates the presence of a complex order par...

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Excess current in superconductingSr2RuO4

Cited by 13 publications

References 31 publications

Vortices in chiral, spin-triplet superconductors and superfluids

Vortices in chiral, spin-triplet superconductors and superfluids

Point-contact spectroscopy in heavy-fermion superconductors

Model Evidence of a Superconducting State with a Full Energy Gap in Small Cuprate Islands

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