Single channel Josephson effect in a high transmission atomic contact

Senkpiel, Jacob; Dambach, Simon; Etzkorn, Markus; Drost, Robert; Padurariu, Ciprian; Kubala, Björn; Belzig, Wolfgang; Yeyati, A. Levy; Cuevas, Juan Carlos; Ankerhold, Joachim; Ast, Christian R.; Kern, Klaus

doi:10.1038/s42005-020-00397-z

Cited by 17 publications

(9 citation statements)

References 39 publications

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“…By extracting the values of I C,NW and I C,C , the dependence of the critical currents on temperature is plotted in Figure 3 b. The red dashed–dotted and gray dotted curves are fits of the temperature dependences of I C,NW and I C,C , respectively, by using the Ambegaokar–Baratoff relation: 40 − 42 where is the superconducting gap at temperature T , 43 − 45 R n is the normal-state resistance, and k B is Boltzmann constant. The temperature dependences of both I C,NW and I C,C are fitted using the coefficient a = 2 and 2.4 and R n = 130 and 143 Ω, respectively.…”

Section: Results and Discussionmentioning

confidence: 99%

Gate-Controlled Supercurrent in Epitaxial Al/InAs Nanowires

et al. 2021

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Gate-controlled supercurrent (GCS) in superconducting nanobridges has recently attracted attention as a means to create superconducting switches. Despite the clear advantages for applications, the microscopic mechanism of this effect is still under debate. In this work, we realize GCS for the first time in a highly crystalline superconductor epitaxially grown on an InAs nanowire. We show that the supercurrent in the epitaxial Al layer can be switched to the normal state by applying ≃±23 V on a bottom gate insulated from the nanowire by a crystalline hBN layer. Our extensive study of the temperature and magnetic field dependencies suggests that the electric field is unlikely to be the origin of GCS in our device. Though hot electron injection alone cannot explain our experimental findings, a very recent non-equilibrium phonons based picture is compatible with most of our results.

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Section: Results and Discussionmentioning

confidence: 99%

Gate-Controlled Supercurrent in Epitaxial Al/InAs Nanowires

et al. 2021

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“…YSR states have been observed on a variety of magnetic atoms -intrinsically present or deliberately placed on the surface -on various superconducting substrates using scanning tunneling microscopy (STM) [11][12][13][14][15]. Due to its capabilities to resolve and manipulate single atoms [7,[16][17][18][19], the STM is ideally suited to realize a tunable coupling between one YSR state at the tip apex and another on the sample surface. Elementary charges tunneling between these two YSR states results in subgap excitations that subsequently relax into the continuum of each superconductor acting as a reservoir.…”

mentioning

confidence: 99%

Tunnelling dynamics between superconducting bound states at the atomic limit

et al. 2020

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Despite plenty of room at the bo om, there is a limit to the miniaturization of every process. For charge transport this is realized by the coupling of single discrete energy levels at the atomic scale. Here, we demonstrate sequential tunneling between parity protected Yu-Shiba-Rusinov (YSR) states bound to magnetic impurities located on the superconducting tip and sample of a scanning tunneling microscope at 10 mK. We reduce the relaxation of the excited YSR state to the bare minimum and nd an enhanced lifetime for single quasiparticle levels. Our work o ers a way to characterize and to manipulate coupled superconducting bound states, such as Andreev levels, YSR states, or Majorana bound states.

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“…However, large scattering range of I SW and R 0 hides possible ef-fect of charging. For the same reason, it is unclear if the impedance of the environment plays any significant role in these experiments: similar values of I SW could be observed for single JJ in a highly-resistive environment (> 100kΩ as in [36] and our setup), single JJ in a low-impedance environment [38], and chains of SQUIDs frustrated by the magnetic field [31,34].…”

Section: In the Regime E Cmentioning

confidence: 74%

“…( 2). [40] 0.17 7..5 0.05 400 Murani 2020 [14] 0.12 5 0.07 Senkpiel 2020 [38] 0.09 0.012 830 Kuzmin 1991 [41] 0.05 1 0.014 8000…”

Section: In the Regime E Cunclassified

Phase Diffusion in Low-$E_J$ Josephson Junctions at milli-Kelvin Temperatures

Lu¹,

Kalashnikov²,

Kamenov³

et al. 2021

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Josephson junctions (JJs) with Josephson energy EJ1K are widely employed as non-linear elements in superconducting circuits for quantum computing, operating at milli-Kelvin temperatures. Here we experimentally study incoherent phase slips (IPS) in low-EJ Aluminum-based JJs at T < 0.2K, where the IPS become the dominant source of dissipation. We observed strong suppression of the critical (switching) current and a very rapid growth of the zero-bias resistance with decreasing Josephson energy below EJ ∼ 1K. This behavior is attributed to the IPSs whose rate exponentially increases with decreasing the ratio EJ /T . Our observations are in line with other data reported in literature. With further improvement of coherence of superconducting qubits, the observed dissipation from IPS might limit the performance of qubits based on low-EJ junctions. Our results point the way to future improvements of such qubits.

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Single channel Josephson effect in a high transmission atomic contact

Cited by 17 publications

References 39 publications

Gate-Controlled Supercurrent in Epitaxial Al/InAs Nanowires

Gate-Controlled Supercurrent in Epitaxial Al/InAs Nanowires

Tunnelling dynamics between superconducting bound states at the atomic limit

Phase Diffusion in Low-$E_J$ Josephson Junctions at milli-Kelvin Temperatures

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