Electrical Characteristics of HoBa2Cu3O7-x-La1.5Ba1.5Cu3O7-y-HoBa2Cu3O7-x Junctions with Planar-Type Structures

Kabasawa, Uki; Tarutani, Y.; Fukazawa, T.; Tsukamoto, Akira; Hiratani, Masahiko; Takagi, Kazumasa

doi:10.1143/jjap.30.1670

Cited by 37 publications

(13 citation statements)

References 7 publications

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“…Experimentally, proximity effect was found to be weaker in the c-axis direction than in the ab-plane direction due to a much shorter co-herence length in the former direction. [89][90][91] We note, however, that so-called giant proximity effect has been reported both in the ab-plane [92][93][94][95] and c-axis 96 directions. Proximity effect in HTSC-ferromagnet and/or HTSC-half-metal heterostructures have also been studied experimentally.…”

Section: Summary and Experimental Implicationsmentioning

confidence: 57%

Topological superconductivity and Majorana fermions in hybrid structures involving cuprate high-Tcsuperconductors

et al. 2013

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The possibility of inducing topological superconductivity with cuprate high-temperature superconductors (HTSC) is studied for various heterostructures. We first consider a ballistic planar junction between a HTSC and a metallic ferromagnet. We assume that inversion symmetry breaking at the tunnel barrier gives rise to Rashba spin-orbit coupling in the barrier and allows equal-spin triplet superconductivity to exist in the ferromagnet. Bogoliubov-de Gennes equations are obtained by explicitly modeling the barrier, and taking account of the transport anisotropy in the HTSC. By making use of the self-consistent boundary conditions and solutions for the barrier and HTSC regions, an effective equation of motion for the ferromagnet is obtained where Andreev scattering at the barrier is incorporated as a boundary condition for the ferromagnetic region. For a ferromagnet layer deposited on a (100) facet of the HTSC, triplet p-wave superconductivity is induced. For the layer deposited on a (110) facet, the induced gap does not have the p-wave orbital character, but has an even orbital symmetry and an odd dependence on energy. For the layer on the (001) facet, an exotic f -wave superconductivity is induced. We also consider the induced triplet gap in a one-dimensional half-metallic nanowire deposited on a (001) facet of a HTSC. Due to the breaking of translational symmetry in the direction perpendicular to the wire axis, the expression for the gap receives contributions from different perpendicular momentum eigenstates in the superconductor. We find that for a wire axis along the a-axis, these different contributions constructively interfere and give rise to a robust triplet p-wave gap. For a wire oriented 45• away from the a-axis the different contributions destructively interfere and the induced triplet p-wave gap vanishes. For the appropriately oriented wire, the induced p-wave gap may give rise to Majorana fermions at the ends of the half-metallic wire. In light of the recent experimental progress in the quest for realizing Majorana fermions, we also discuss inducing superconductivity in the spin-orbit coupled nanowire using a HTSC. Based on our result, topological superconductivity in a semi-conductor nanowire may be possible given that it is oriented along the a-axis of the HTSC.

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Section: Summary and Experimental Implicationsmentioning

confidence: 57%

Topological superconductivity and Majorana fermions in hybrid structures involving cuprate high-Tcsuperconductors

et al. 2013

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“…[6,7]. Barholz et al [18] observed no supercurrent in coplanar junctions with trenches down to 50 nm; they ascribed previous findings [4,5,10] to HTS microshorts formed by inadvertent resputtering of YBa 2 Cu 3 O 7 (YBCO). Yoshida [19] revisited ab-plane step-edge junctions with YBCO electrodes and Co-doped PBCO as the barrier; he found that n 6 A, which is 2 orders of magnitude less than what was claimed before.…”

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confidence: 97%

“…While in this Letter we have considered barriers up to 200 Å thick, the supercurrent was sizeable, and it is clear that the maximum coupling distance should be at least several times larger, even in our c-axis geometry-and conceivably longer in the more favorable a-axis geometry (as in Refs. [4][5][6][7][8][9][10][11]). …”

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confidence: 99%

Giant Proximity Effect in Cuprate Superconductors

Božović

Логвенов²,

Verhoeven³

et al. 2004

Phys. Rev. Lett.

166

163

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Using an advanced molecular beam epitaxy system, we have reproducibly synthesized atomically smooth films of high-temperature superconductors and uniform trilayer junctions with virtually perfect interfaces. We found that supercurrent runs through very thick barriers. We can rule out pinholes and microshorts; this "giant proximity effect" (GPE) is intrinsic. It defies the conventional explanation; it might originate in resonant tunneling through pair states in an almost-superconducting barrier. GPE may also be significant for superconducting electronics, since thick barriers are easier to fabricate.

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“…Indeed, numerous groups have demonstrated a high T c proximity effect with insulating cuprates [34,35,36,37,38], Au quantum dots [39], and in LCMO/YBCO thin films [40,41,42,43]. Recently we were able to achieve a proximity effect between Bi 2 Sr 2 CaCu 2 O 8+δ [44] and two heavily doped topological insulators (Bi 2 Se 3 , Bi 2 Te 3 ), which are known to superconduct with heavy doping [45,46] or pressure [47].…”

Section: Introductionmentioning

confidence: 99%

Modeling tunneling for the unconventional superconducting proximity effect

Zareapour

Zhao

et al. 2016

Supercond. Sci. Technol.

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Recently there has been reinvigorated interest in the superconducting proximity effect, driven by predictions of the emergence of Majorana fermions. To help guide this search, we have developed a phenomenological model for the tunneling spectra in anisotropic superconductor-normal metal proximity devices. We combine successful approaches used in s-wave proximity and standard d-wave tunneling to reproduce tunneling spectra in d-wave proximity devices, and clarify the origin of various features. Different variations of the pair potential are considered, resulting from the proximity-induced superconductivity. Furthermore, the effective pair potential felt by the quasiparticles is momentum-dependent in contrast to s-wave superconductors. The probabilities of reflection and transmission are calculated by solving the Bogoliubov equations. Our results are consistent with experimental observations of the unconventional proximity effect and provide important experimental parameters such as the size and length scale of the proximity induced gap, as well as the conditions needed to observe the reduced and full superconducting gaps.

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Electrical Characteristics of HoBa₂Cu₃O_7-x-La_1.5Ba_1.5Cu₃O_7-y-HoBa₂Cu₃O_7-x Junctions with Planar-Type Structures

Cited by 37 publications

References 7 publications

Topological superconductivity and Majorana fermions in hybrid structures involving cuprate high-Tcsuperconductors

Topological superconductivity and Majorana fermions in hybrid structures involving cuprate high-Tcsuperconductors

Giant Proximity Effect in Cuprate Superconductors

Modeling tunneling for the unconventional superconducting proximity effect

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