Quasiparticle current in ballistic constrictions with finite transparencies of interfaces

Aminov, B. A.; Golubov, A. A.; Kupriyanov, M. Yu.

doi:10.1103/physrevb.53.365

Cited by 93 publications

(84 citation statements)

References 23 publications

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“…The assumption of an induced hard gap is justified if the SC-NW interface is in the tunneling regime. This seems to be a reasonable assumption since the experimentally reported induced gaps are much smaller than the parent bulk SC gaps [24][25][26], a fact that typically occurs in low-transmittance interfaces [34,36,37] (As a word of caution, the experimental evidence for this identification is still limited and other explanations cannot be completely ruled out). In the tunneling regime, the quantity γ i = ρ 0 t 2…”

mentioning

confidence: 99%

Soft Superconducting Gap in Semiconductor Majorana Nanowires

et al. 2013

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We theoretically consider the ubiquitous soft gap measured in the tunneling conductance of semiconductorsuperconductor hybrid structures, in which recently observed signatures of elusive Majorana bound states have created much excitement. We systematically study the effects of magnetic and non-magnetic disorder, temperature, dissipative Cooper pair breaking, and interface inhomogeneity, which could lead to a soft gap. We find that interface inhomogeneity with moderate dissipation is the only viable mechanism that is consistent with the experimental observations. Our work indicates that improving the quality of the superconductor-semiconductor interface should result in a harder induced gap.

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confidence: 99%

Soft Superconducting Gap in Semiconductor Majorana Nanowires

et al. 2013

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“…2(a) for temperatures in the range from 2 to 7 K. The distinct peak and the lowering of dV /dI at its lower bias side can be attributed to the onset of multiple Andreev reflection. 20,21 The relatively small decrease of differential resistance at the lower bias side of the peak by about 10% compared to the higher bias side can be attributed to the presence of an interface barrier. 20,21 As can be seen in Fig.…”

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confidence: 99%

“…20,21 The relatively small decrease of differential resistance at the lower bias side of the peak by about 10% compared to the higher bias side can be attributed to the presence of an interface barrier. 20,21 As can be seen in Fig. 2(b) (inset), more structures are found in the differential resistance by approaching zero bias.…”

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confidence: 99%

Josephson supercurrent in Nb/InN-nanowire/Nb junctions

Frielinghaus

Batov

Weides

et al. 2010

Applied Physics Letters

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We experimentally studied the Josephson supercurrent in Nb/InN-nanowire/Nb junctions. Large critical currents up to 5.7 µA have been achieved, which proves the good coupling of the nanowire to the superconductor. The effect of a magnetic field perpendicular to the plane of the Josephson junction on the critical current has been studied. The observed monotonous decrease of the critical current with magnetic field is explained by the magnetic pair-breaking effect in planar Josephson junctions of ultra-narrow width [J. C. Cuevas and F. S. Bergeret, Phys. Rev. Lett. 99, 217002 (2007)] Superconductor/normal-conductor/superconductor (SNS) junctions with a semiconductor employed as the N-weak link material offer the great advantage that here the Josephson supercurrent can be controlled by means of the field effect. 1,2 Gate-controlled superconductor/semiconductor hybrid devices such as superconducting field effect transistors 3 or split-gate structures 4 have been fabricated which find no counterpart in conventional SNS structures. In addition, the high carrier mobility attainable in semiconductors in combination with the phase-coherent Andreev reflection leads to novel unique phenomena in the magnetotransport. 5-7 Usually for these devices the semiconductor is patterned by conventional lithography. As an elegant alternative one can also directly create semiconductor nanostructures, i.e. nanowires, by epitaxial growth. 8 By using InAs nanowires connected to superconducting electrodes tunable Josephson supercurrents, supercurrent reversal, and Kondo-enhanced Andreev tunneling have been realized. [9][10][11] Among the various materials used for semiconductor nanowires InN is of particular interest for semiconductor/superconductor hybrid structures, since the surface accumulation layer in InN can provide a sufficiently low resistive contact to superconducting electrodes. 12-14 Due to almost ideal crystalline properties of InN nanowires electronic transport along the wires, contacted by normal metal electrodes, shows quantization phenomena, i.e. flux periodic magnetoconductance oscillations. 15 Furthermore, the carrier concentration in the surface electron gas is of the order of 10 13 cm −2 and thus about a factor of ten larger than in InAs. Consequently when combined with superconducting electrodes one can expect low resistive SNS junctions.Here, we report on transport studies of Nb/InNnanowire/Nb junctions. We succeeded in observing a pronounced Josephson supercurrent and a relatively large I c R N product of up to 0.44 mV. The latter factor, the critical current times the normal resistance, is an important figure of merit for Josephson junctions. We devoted special attention to the dependence of the critical current I c on an external magnetic field B, where a monotonous decrease of I c with B was found. This experimental finding is interpreted in the framework of a recent theoretical model for the proximity effect in narrow-width junctions with dimensions comparable or smaller than the magnetic length ξ B = Φ 0 /B,...

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“…In Fig. 6b, the differential resistance dV/dI as a function of the bias voltage is plotted at temperatures from 2 to 8 K. The distinct peaks at 2 and 3 K, are recognized as the result from Andreev reflection under a superconducting state [43,44], in which electrons/holes will be reflected from the interfaces of junction. The Andreev reflection and resultant excess conductance originates from the interfaces in Sn/CNT/Sn junctions of Sn@CNT NRs.…”

Section: Superconductivity Of Sn@cnt Nrs Below T Cmentioning

confidence: 99%