Anomalous Proximity Effect in the Nb-BiSb-Nb Junctions

Kasumov, A.; Кононенко, О. В.; Матвеев, В. Н.; Borsenko, T B; Tulin, V. A.; Вдовин, Е. Е.; Khodos, I. I.

doi:10.1103/physrevlett.77.3029

Cited by 24 publications

(24 citation statements)

References 17 publications

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“…Among various proposed schemes, a typical one is to create MF at the interface between a conventional s -wave superconductor and a 3D topological insulator (TI)111213, where a proximity-induced state resembling a spinless p x +ip y superconductor is expected to occur. Experimentally, progresses have recently been made in the observations of a supercurrent over a relatively long distance in Nb-BiSb-Nb, Al-Bi 2 Te 3 -Al and W-Bi 2 Se 3 -W devices141516, a perfect Andreev reflection of the helical mode in InAs/GaSb quantum wells17, and the opening of gap-like structures together with a conductance peak at the Fermi level in Sn-Bi 2 Se 3 devices18. However, further characterizations are still needed to clarify the nature of the superconductor-topological insulator interface.…”

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confidence: 99%

Strong Superconducting Proximity Effect in Pb-Bi2Te3 Hybrid Structures

Yang

Shen

et al. 2012

Sci Rep

133

164

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To study the interface between a conventional superconductor and a topological insulator, we fabricated Pb-Bi2Te3-Pb lateral and sandwiched junctions, and performed electron transport measurements down to low temperatures. The results show that there is a strong superconducting proximity effect between Bi2Te3 and Pb, as that a supercurrent can be established along the thickness direction of the Bi2Te3 flakes (100~300 nm thick) at a temperature very close to the superconducting Tc of Pb. Moreover, a Josephson current can be established over several microns in the lateral direction between two Pb electrodes on the Bi2Te3 surface. We have further demonstrated that superconducting quantum interference devices can be constructed based on the proximity-effect-induced superconductivity. The critical current of the devices exhibits s-wave-like interference and Fraunhofer diffraction patterns. With improved designs, Josephson devices of this type would provide a test-bed for exploring novel phenomena such as Majorana fermions in the future.

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confidence: 99%

Strong Superconducting Proximity Effect in Pb-Bi2Te3 Hybrid Structures

Yang

Shen

et al. 2012

Sci Rep

133

164

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“…Furthermore, the "locking" of spin and momentum in TI surface states raises important theoretical questions about the nature of the proximity effect at TI/superconductor junctions 7 and recent experiments suggest that the measurement geometry could have a significant influence on the observed phenomena 8 . Evidence for the proximity effect was provided in an early study 9 that interfaced a superconductor with Bi 1−x Sb x , a material now recognized 10,11 as a 3D TI. More recently 12 , a supercurrent was observed in thin exfoliated samples of another TI (Bi 2 Se 3 ).…”

Section: Introductionmentioning

confidence: 99%

Superconducting proximity effect and possible evidence for Pearl vortices in a candidate topological insulator

Zhang¹,

Wang²,

DaSilva³

et al. 2011

Phys. Rev. B

137

141

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We report the observation of the superconducting proximity effect in nanoribbons of a candidate topological insulator (Bi2Se3) which is interfaced with superconducting (tungsten) contacts. We observe a supercurrent and multiple Andreev reflections for channel lengths that are much longer than the inelastic and diffusive thermal lengths deduced from normal state transport. This suggests that the proximity effect couples preferentially to a ballistic surface transport channel, even in the presence of a coexisting diffusive bulk channel. When a magnetic field is applied perpendicular to the plane of the nanoribbon, we observe magnetoresistance oscillations that are periodic in magnetic field. Quantitative comparison with a model of vortex blockade relates the occurrence of these oscillations to the formation of Pearl vortices in the region of proximity induced superconductivity.

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“…58). The challenge here is to find a material whose band gap is comparable to the typical critical temperature of the superconducting layer.…”

Section: Discussionmentioning

confidence: 99%

Cooper pair insulators and theory of correlated superconductors

Nikolić

Tešanović

2011

Phys. Rev. B

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The pseudogap state of cuprate high-temperature superconductors has been often viewed as either a yet unknown competing order or a precursor state to superconductivity. While awaiting the resolution of the pseudogap problem in cuprates, we demonstrate that local pairing fluctuations, vortex liquid dynamics, and other precursor phenomena can emerge quite generally whenever fermionic excitations remain gapped across the superconducting transition, regardless of the gap origin. Our choice of a tractable model is a lattice band insulator with short-range attractive interactions between fermions in the s-wave channel. An effective crossover between Bardeen-Cooper-Schrieffer (BCS) and Bose-Einstein condensate (BEC) regimes can be identified in any band insulator above two dimensions, while in two dimensions only the BEC regime exists. The superconducting transition is "unconventional" (non-pair-breaking) in the BEC regime, identified by either the bosonic mean field or XY universality class. The insulator adjacent to the superconductor in the BEC regime is a bosonic Mott insulator of Cooper pairs, which may be susceptible to charge density wave ordering. We construct a function of the many-body excitation spectrum whose nonanalytic changes define a sharp distinction between band and Mott insulators. The corresponding "second-order transition" can be observed out of equilibrium by driving a Cooper pair laser in the Mott insulator. We explicitly show that the gap for charged bosonic excitations lies below the threshold for Cooper pair breakup in any BEC regime, despite quantum fluctuations. Our discussion ends with a view of possible consequences for cuprates, where antinodal pair dynamics has certain features in common with our simple s-wave picture.

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Anomalous Proximity Effect in the Nb-BiSb-Nb Junctions

Cited by 24 publications

References 17 publications

Strong Superconducting Proximity Effect in Pb-Bi2Te3 Hybrid Structures

Strong Superconducting Proximity Effect in Pb-Bi2Te3 Hybrid Structures

Superconducting proximity effect and possible evidence for Pearl vortices in a candidate topological insulator

Cooper pair insulators and theory of correlated superconductors

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