Joint measurement of current-phase relations and transport properties of hybrid junctions using a three junctions superconducting quantum interference device

Basset, Julien; Delagrange, R.; Weil, Raphaël; Kasumov, A.; Bouchiat, H.; Deblock, R.

doi:10.1063/1.4887354

Cited by 10 publications

(14 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1 a). This device, a SQUID containing the QD JJ (here the CNT) and a reference JJ with critical current high compared to the one of the QD JJ, allows us to determine the CPR of interest [31,32]. The switching current I s of the SQUID versus magnetic flux is measured.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Manipulating the magnetic state of a carbon nanotube Josephson junction using the superconducting phase

et al. 2015

Self Cite

View full text Add to dashboard Cite

The magnetic state of a quantum dot attached to superconducting leads is experimentally shown to be controlled by the superconducting phase difference across the dot. This is done by probing the relation between the Josephson current and the superconducting phase difference of a carbon nanotube junction whose Kondo energy and superconducting gap are of comparable size. It exhibits distinctively anharmonic behavior, revealing a phase mediated singlet to doublet transition. We obtain an excellent quantitative agreement with numerically exact quantum Monte Carlo calculations. This provides strong support that we indeed observed the finite temperature signatures of the phase controlled zero temperature level-crossing transition originating from strong local electronic correlations.PACS number(s): 74.50.+r, 72.15.Qm, 73.63.Fg When a localized magnetic moment interacts with a Fermi sea of conduction electrons, the Kondo effect can develop: spin-flip processes lead to a many-body singlet state in which the delocalized electrons screen the moment. Quantum dots (QD) in the Coulomb blockade regime and particularly carbon nanotube (CNT) dots constitute ideal systems for the investigation of Kondo physics at the single spin level [1][2][3]. In these systems, it is possible to control the number of electrons on the dot varying a gate voltage. For an odd occupation, the dot accommodates a magnetic moment which is screened provided that this is not prohibited by an energy scale larger than the Kondo energy k B T K . Temperature is the most obvious obstacle to the development of the Kondo effect since T K can be smaller than 1K. However, if temperature is sufficiently low, the Kondo effect may compete with other quantum many-body phenomena such as superconductivity, for which the formation of Cooper pairs of energy ∆ may prevent the screening of the dot's spin. This situation can be investigated using superconducting hybrid junctions, where a supercurrent is induced by the proximity effect, for example in or semiconductor-based ones [5].A setup of a high resistance tunnel barrier between two superconductors, also called Josephson junction (JJ), carries a supercurrent I = I C sin ϕ, with the critical current I C . The superconducting phase difference across the junction ϕ controls the amplitude and the sign of the supercurrent. This is the Josephson relation, the most famous example of a current-phase relation (CPR). In some peculiar systems such as ferromagnetic superconducting junctions, the transmission of Cooper pairs gives rise to a π phase shift of the CPR [6]. In QD JJs (tunnel barrier replaced by QD) in the strong Coulomb blockade regime where the Kondo effect is negligible, such a π shift is observed as well since the tunneling of a Cooper pair implies reversing the order of particles within this pair. This leads to a gate-controlled sign reversal of the CPR when the parity of the number of electrons is changed, as was observed experimentally [7][8][9][10]. In contrast, if the Kondo effect and thus local correlations...

show abstract

mentioning

confidence: 99%

“…Our device possesses a second reference JJ and a third connection as described in Ref. [32]. This allows us to characterize each junction independently at room temperature, and to measure both the CPR of the CNT and its differential conductance in the superconducting state.…”

mentioning

confidence: 99%

Manipulating the magnetic state of a carbon nanotube Josephson junction using the superconducting phase

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…As discussed above, the current-phase relation provides detailed insights into the singlet-triplet ratio of a NCSC. Unfortunately, measuring current-phase relations for nanoscale circuits is experimentally very challenging (though the current-phase relation of a small Josephson junction as well as of a carbon nanotube junction was recently detected experimentally [46]). Quantities that are routinely measured for mesoscopic Josephson junctions are the critical currents, i.e., the maximal supercurrent that can flow through the device.…”

Section: Critical Currentmentioning

confidence: 99%

Josephson response of a conventional and a noncentrosymmetric superconductor coupled via a double quantum dot

Sothmann,

Tiwari

2015

Preprint

View full text Add to dashboard Cite

We consider transport through a Josephson junction consisting of a conventional s-wave superconductor coupled via a double quantum dot to a noncentrosymmetric superconductor with both, singlet and triplet pairing. We calculate the Andreev bound state energies and the associated Josephson current. We demonstrate that the current-phase relation is a sensitive probe of the singlet-triplet ratio in the noncentrosymmetric superconductor. In particular, in the presence of an inhomogeneous magnetic field the system exhibits a ϕ-junction behavior.

show abstract

“…Unfortunately, measuring current-phase relations for nanoscale circuits is experimentally very challenging (though the current-phase relation of a small Josephson junction as well as of a carbon nanotube junction was recently detected experimentally [46]). Quantities that are routinely measured for mesoscopic Josephson junctions are the critical currents, i.e., the maximal supercurrent that can flow through the device.…”

Section: Critical Currentmentioning

confidence: 99%

Josephson response of a conventional and a noncentrosymmetric superconductor coupled via a double quantum dot

Sothmann

Tiwari

2015

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

Joint measurement of current-phase relations and transport properties of hybrid junctions using a three junctions superconducting quantum interference device

Cited by 10 publications

References 27 publications

Manipulating the magnetic state of a carbon nanotube Josephson junction using the superconducting phase

Manipulating the magnetic state of a carbon nanotube Josephson junction using the superconducting phase

Josephson response of a conventional and a noncentrosymmetric superconductor coupled via a double quantum dot

Josephson response of a conventional and a noncentrosymmetric superconductor coupled via a double quantum dot

Contact Info

Product

Resources

About