Tunable interplay between superconductivity and correlations in nanoscopic heterostructures

Domański, T.; Barański, Jan; Zapalska, M.

doi:10.1080/14786435.2014.965766

Cited by 3 publications

(2 citation statements)

References 41 publications

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“…In this, so-called deep superconducting atomic limit, the influence of a superconducting background on each quantum dot can be reduced to static sources and sinks of local pairs [23][24][25]. Hamiltonian of each quantum dot (j = 1, 2) placed in proximity of superconductor, in noncorrelated regime can be represented bŷ…”

Section: Modelmentioning

confidence: 99%

Interferometric Signatures of Electron Transfer through Majorana Bound States

Barański

Zienkiewicz

2019

Acta Phys. Pol. A

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In semiconducting nanowires deposited on top of s-wave superconductors, the combined effect of induced superconducting order, strong spin-orbit coupling, and magnetic field can lead to the realization of topologically non-trivial edge states. According to Kitayev's model, such states fulfill the axioms of Majorana quasiparticles. Recent development of quantum dot-nanowire hybrids provides useful tools to perform analysis which goes beyond mere observation of such states. One of the most challenging tasks is to demonstrate the nonlocal character of these states. Considering two quantum dots coupled to opposite edges of a chain hosting Majorana quasi-particles, we show that long range electron transfer through the Majorana states can be demonstrated by measurement of local currents. We show that the scattering of electron on one dot gives rise to interferometric signatures on the quantum dot connected to the opposite side of the nanowire.

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Section: Modelmentioning

confidence: 99%

Interferometric Signatures of Electron Transfer through Majorana Bound States

Barański

Zienkiewicz

2019

Acta Phys. Pol. A

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“… , the influence of superconducting electrode on interfacial quantum dot QD 1 is reduced to the induced local pairing. A problem of the "proximized" quantum dot was widely explored by many authors 2,73-77 including ourselfs 3,[78][79][80] . In such conditions, the Hamiltonian of the interfacial dot coupled to the SC reservoir (i.e.,…”

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confidence: 99%

Anomalous Fano Resonance in Double Quantum Dot System Coupled to Superconductor

Barański¹,

Zienkiewicz²,

Barańska³

et al. 2020

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We analyze the influence of a local pairing on the quantum interference in nanoscopic systems. As a model system we choose the double quantum dot coupled to one metallic and one superconducting electrode in the T-shape geometry. The analysis is particularly valuable for systems containing coupled objects with considerably different broadening of energy levels. In such systems, the scattering of itinerant electrons on a discrete (or narrow) energy level gives rise to the Fano-type interference. Systems with induced superconducting order, along well understood Fano resonances, exhibit also another features on the opposite side of the Fermi level. The lineshape of these resonances differs significantly from their reflection on the opposite side of the Fermi level, and their origin was not fully understood. Here, considering the spin-polarized tunneling model, we explain a microscopic mechanism of a formation of these resonances and discuss the nature of their uncommon lineshapes. We show that the anomalous Fano profiles originate solely from the pairing of nonscattered electrons with scattered ones. We investigate also the interplay of each type of resonances with the Kondo physics and discuss the resonant features in differential conductivity.

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Hybrid quantum dot–superconducting systems: Josephson current and Kondo effect in the narrow-band limit

Allub

Proetto

2015

Phys. Rev. B

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The case of a quantum dot connected to two superconducting leads is studied by using the narrow-band limit to describe the superconducting degrees of freedom. The model provides a simple theoretical framework, almost analytical, to analyze the interplay between the Kondo effect, superconductivity, and finite temperature. In the quantum dot Kondo regime, the model is completely characterized by the ratio /J , with the superconducting gap and J an effective antiferromagnetic exchange coupling between the dot and the leads. The model allows us to calculate, at any temperature T , the equilibrium Josephson current through the dot in a very straightforward way as a function of /J . The behavior of the current allows us to distinguish the four types of hybrid junctions: 0, 0 , π , and π . The presence of the 0-and 0 -junction configurations are intrinsically linked to the Kondo effect in the quantum dot, while the π -and π -junction configurations are driven by the superconductivity in the leads. The Josephson critical current has a non-monotonic behavior with temperature, that may be used for the experimental characterization of the fundamental 0 − π transition. The model allows us to obtain easily a phase diagram /J vs temperature, from where we can obtain an overall picture on the stability of the different types of junctions. From the explicit analytical expressions for the ground-state, low-energy excitations, free energy, and Josephson current, it is easy to understand the physical nature of the main features of the critical current and the phase diagram. The results, obtained with a minimum of numerical effort, are in a good qualitative agreement with more demanding calculational approaches aimed to solve the full model.

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Tunable interplay between superconductivity and correlations in nanoscopic heterostructures

Cited by 3 publications

References 41 publications

Interferometric Signatures of Electron Transfer through Majorana Bound States

Interferometric Signatures of Electron Transfer through Majorana Bound States

Anomalous Fano Resonance in Double Quantum Dot System Coupled to Superconductor

Hybrid quantum dot–superconducting systems: Josephson current and Kondo effect in the narrow-band limit

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