Search for spontaneous edge currents and vortex imaging in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>Sr</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mi>Ru</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>mesostructures

Curran, P. J.; Bending, S. J.; Desoky, W.M.; Gibbs, Alexandra S.; Lee, Stephen; Mackenzie, A. P.

doi:10.1103/physrevb.89.144504

Cited by 88 publications

(93 citation statements)

References 40 publications

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“…2). Although reliant on fine-tuning of parameters, this result might be important for reconciling chiral p-wave superconductivity in Sr 2 RuO 4 21-24 with the null results of experiments designed to measure the expected magnetic fields [8][9][10][11] .…”

Section: Introductionmentioning

confidence: 99%

Nontopological nature of the edge current in a chiralp-wave superconductor

et al. 2015

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The edges of time reversal symmetry breaking topological superconductors support chiral Majorana bound states as well as spontaneous charge currents. The Majorana modes are a robust, topological property, but the charge currents are non-topological-and therefore sensitive to microscopic details-even if we neglect Meissner screening. We give insight into the non-topological nature of edge currents in chiral p-wave superconductors using a variety of theoretical techniques, including lattice Bogoliubov-de Gennes equations, the quasiclassical approximation, and the gradient expansion, and describe those special cases where edge currents do have a topological character. While edge currents are not quantized, they are generically large, but can be substantially reduced for a sufficiently anisotropic gap function, a scenario of possible relevance for the putative chiral p-wave superconductor Sr2RuO4.

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Section: Introductionmentioning

confidence: 99%

Nontopological nature of the edge current in a chiralp-wave superconductor

et al. 2015

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“…The strongest candidate for the spatial symmetry is chiral p-wave order, with d-vector d = ∆ 0ẑ (k x ± ik y ) [6,7], although the exact gap structure is still disputed [8][9][10][11]. For example, spontaneous edge currents, associated with chiral p-wave pairing, have so far not been found [12]. The situation is further complicated by the Fermi surface consisting of three bands originating from three hybridizing Ru 4d orbitals; electron-like γ-(from xy orbital) and β-bands (xz, yz orbitals) and hole-like α-band (xz and yz orbitals).…”

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confidence: 99%

Odd-Frequency Superconductivity in Sr2RuO4 Measured by Kerr Rotation

Komendová

Black‐Schaffer

2017

Phys. Rev. Lett.

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We establish the existence of bulk odd-frequency superconductivity in Sr2RuO4 and show that an intrinsic Kerr effect is a direct evidence of this state. We use both general two-and three-orbital models, as well as a realistic tight-binding description of Sr2RuO4 to demonstrate that odd-frequency pairing arises due to finite hybridization between different orbitals in the normal state, and is further enhanced by finite inter-orbital pairing.The layered perovskite strontium ruthenate Sr 2 RuO 4 hosts an exotic superconducting state at low temperatures [1], with experiments having established both spintriplet pairing [2,3] and broken time-reversal symmetry [4,5]. The strongest candidate for the spatial symmetry is chiral p-wave order, with d-vector d = ∆ 0ẑ (k x ± ik y ) [6,7], although the exact gap structure is still disputed [8][9][10][11]. For example, spontaneous edge currents, associated with chiral p-wave pairing, have so far not been found [12]. The situation is further complicated by the Fermi surface consisting of three bands originating from three hybridizing Ru 4d orbitals; electron-like γ-(from xy orbital) and β-bands (xz, yz orbitals) and hole-like α-band (xz and yz orbitals).In this work we establish that the multi-orbital nature of Sr 2 RuO 4 hosts bulk odd-frequency (odd-ω) superconductivity. Odd-ω superconductivity is a dynamical phenomenon where the fermionic nature of the Cooper pair is preserved due to an oddness in frequency (or equivalently time) [13,14]. It is well established to exist in superconductor-ferromagnet junctions [15][16][17][18][19] and also predicted for superconductor-normal metal junctions [20][21][22]. However, odd-ω superconductivity has remained elusive in bulk materials without external magnetic fields. Recently, an intriguing possibility of bulk odd-ω pairing was proposed for model two-band superconductors. Here an odd parity in the band index of the Cooper pair induces an odd-ω dependence [23,24]. We demonstrate odd-ω superconductivity in Sr 2 RuO 4 arising from a similar odd parity in the orbital index.Importantly, we also show that a finite Kerr rotation angle in clean Sr 2 RuO 4 is direct evidence of odd-ω superconductivity. Detecting the Kerr effect in superconducting Sr 2 RuO 4 was instrumental for establishing timereversal symmetry breaking [4]. Recently, it has also been shown that inter-orbital processes are needed for a finite Kerr rotation [25][26][27][28], unless invoking extrinsic impurity effects [29,30]. We find odd-ω superconductivity and Kerr rotation emerging from the same finite hybridization between different orbitals and supplemented by possible finite inter-orbital pairing.Two-orbital superconductor.-To establish odd-ω superconductivity in Sr 2 RuO 4 and its connection to the Kerr effect we start by studying a minimal two-orbital model. The general Bogoliubov-de Gennes Hamiltonian reads k Ψ † kĤ k Ψ k , wherêand Ψ † k = (c † k↑1 c † k↑2 c −k↓1 c −k↓2 ) for orbitals 1 and 2. The normal and superconducting parts of the Hamiltonian are, respectively,We...

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“…Though this is the leading phenomenological hypothesis, it is seemingly contradicted by several experiments. Prominent among these are high resolution scanning magnetometry measurements [9][10][11] , which image magnetic fields across several µm of sample (including the sample edge) and see no sign of the expected spontaneous currents.…”

Section: Introductionmentioning

confidence: 99%

Suppression of spontaneous currents inSr2RuO4by surface disorder

et al. 2014

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A major challenge to the chiral p-wave hypothesis for the pairing symmetry of the unconventional superconductor Sr2RuO4 is the null result of sensitive scanning magnetometry experiments designed to detect the expected spontaneous charge currents. Motivated by junction tunneling conductance measurements which indicate the quenching of superconductivity at the surfaces of even high-purity samples, we examine the spontaneous currents in a chiral p-wave superconductor near a normal metal / superconductor interface using the lattice Bogoliubov-de Gennes equations and Ginzburg-Landau theory, and find that the edge current is suppressed by more than an order of magnitude compared to previous estimates. These calculations demonstrate that interface details can have a quantitatively meaningful effect on the expectations for magnetometry experiments.

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Search for spontaneous edge currents and vortex imaging inSr2RuO4mesostructures

Cited by 88 publications

References 40 publications

Nontopological nature of the edge current in a chiralp-wave superconductor

Nontopological nature of the edge current in a chiralp-wave superconductor

Odd-Frequency Superconductivity in Sr2RuO4 Measured by Kerr Rotation

Suppression of spontaneous currents inSr2RuO4by surface disorder

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