Andreev levels spectroscopy of topological three-terminal junctions

Valentini, Stefano; Fazio, Rosario; Taddei, F.

doi:10.1103/physrevb.89.014509

Cited by 14 publications

(18 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We also note that the STM tips can also be used in a similar way to extract the information about the spatial profile of other than MFs types of bound states, such as fractional fermion states or Andreev bound states [46][47][48][49].…”

Section: Discussionmentioning

confidence: 99%

Tomography of Majorana fermions with STM tips

Chevallier

Klinovaja

2016

Phys. Rev. B

View full text Add to dashboard Cite

We investigate numerically the possibility to detect the spatial profile of Majorana fermions (MFs) by using STM tips that are made of either normal or superconducting material. In both cases, we are able to resolve the localization length and the oscillation period of the MF wave function. We show that the tunneling between the substrate and the tip, necessary to get the information on the wave-function oscillations, has to be weaker in the case of a superconducting probe. In the strong tunneling regime, the differential conductance saturates making it more difficult to observe the exponential decay of MFs. The temperature broadening of the profile is strongly suppressed in the case of the superconducting tip resulting, generally, in better resolution.

show abstract

Section: Discussionmentioning

confidence: 99%

Tomography of Majorana fermions with STM tips

Chevallier

Klinovaja

2016

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…In the low-transparency regime, power dissipation could be strongly limited 37 and Andreev bound state spectroscopy might be also achieved 38 . Finally, in presence of an appropriate magnetic field, the device could be an important tool for the investigation of topological superconductivity 12 and long-range triplet superconducting correlations 17,18 .…”

mentioning

confidence: 99%

“…Up to now, most of the related experimental works have been focused on the study of hybrid devices based on diffusive semiconductor nanowires 9,10 , normal metals 5,6 and ferromagnets 7 . Nevertheless, the structure flexibility and the reduced influence of disorder candidate S-2DEG systems as a promising platform to reach the complete understanding of these effects 11,12 . One of the first steps toward this scope is the fabrication of a ballistic S-2DEG interferometer, in which the phase of quasiparticles is controlled by an external magnetic field and the number of conducting channels can be tailored at will thanks to the presence of side gates.…”

mentioning

confidence: 99%

A ballistic two-dimensional-electron-gas Andreev interferometer

Amado

Fornieri

Biasiol

et al. 2014

Applied Physics Letters

View full text Add to dashboard Cite

We report the realization and investigation of a ballistic Andreev interferometer based on an InAs two dimensional electron gas coupled to a superconducting Nb loop. We observe strong magnetic modulations in the voltage drop across the device due to quasiparticle interference within the weak-link. The interferometer exhibits flux noise down to ∼ 80 µΦ 0 / √ Hz, and a robust behavior in temperature with voltage oscillations surviving up to ∼ 7 K. Besides this remarkable performance, the device represents a crucial first step for the realization of a fully-tunable ballistic superconducting magnetometer and embodies a potential advanced platform for the investigation of Majorana bound states, non-local entanglement of Cooper pairs, as well as the manipulation and control of spin triplet correlations.The combination of ballistic two-dimensional-electrongases (2DEGs) and superconductors (S) may represent a key tool for the investigation of Majorana bound states 1-4 , the generation of solid-state entanglers 5,6 as well as spin triplet superconductivity 7,8 . Up to now, most of the related experimental works have been focused on the study of hybrid devices based on diffusive semiconductor nanowires 9,10 , normal metals 5,6 and ferromagnets 7 . Nevertheless, the structure flexibility and the reduced influence of disorder candidate S-2DEG systems as a promising platform to reach the complete understanding of these effects 11,12 . One of the first steps toward this scope is the fabrication of a ballistic S-2DEG interferometer, in which the phase of quasiparticles is controlled by an external magnetic field and the number of conducting channels can be tailored at will thanks to the presence of side gates. The realization of this kind of device must fulfill two essential conditions: (i) a Schottky barrier-free normal regionsuperconductor interface is necessary to couple the superconductor with the weak link leading to a robust proximity effect, and (ii) the geometrical dimensions of the 2DEG-region must lie below the electron elastic mean free path ensuring the ballistic transport of quasiparticles in the normal region. In the last few years, the major efforts have been put on InAs and InAs/AlSb 2DEG-based hybrid structures. These materials exhibit a larger g-factor and spin-orbit coupling in comparison to those existing in In 0.75 Ga 0.25 As semiconductor alloys [13][14][15][16] , being therefore more attractive for the implementation of a topological non-trivial phase 1-3 . Moreover, the interplay between spin-orbit coupling and spin-splitting (due to the application of an external magnetic field) may lead to an advanced manipulation and control of the triplet superconducting correlations 17,18 with potential application in spintronics. While the early generation of magnetic-flux controlled interferometers consisted of a normal metal (N) region connected to ring-shaped superconductors [19][20][21][22][23][24] , the first realization of a 2DEG-based quasiparticle interferometer was reported by Dimoulas et al. 25 , where ...

show abstract

“…4(a) demonstrate that the kinetic inductance of the Josephson weak link can be tuned by h ex , and maximized around ∼ π. This is indeed essential to provide a robust and well-defined phase drop across the junction in a number of nanodevices 32,[35][36][37][38][39] …”

mentioning

confidence: 99%

“…−1 ] in a region of phases (ϕ ∼ π) very important for several phase-controlled devices 32,[35][36][37][38][39] . In order to quantify the relative deviation of the CPR from the sinusoidal behavior we plot in Fig.…”

mentioning

confidence: 99%

Mesoscopic Josephson junctions with switchable current-phase relation

Strambini

Bergeret

Giazotto

2015

EPL

View full text Add to dashboard Cite

We propose and analyze a mesoscopic Josephson junction consisting of two ferromagnetic insulatorsuperconductors (FI-Ss) coupled through a normal metal (N) layer. The Josephson current of the junction is non-trivially affected by the spin-splitting field induced by the FIs in the two superconductors. In particular, it shows sizeable enhancement by increasing the amplitude of the exchange field (h ex ) and displays a switchable current-phase relation which depends on the relative orientation of h ex in the FIs. In a realistic EuS/Al-based setup this junction can be exploited as a high-resolution threshold sensor for the magnetic field as well as an on-demand tunable kinetic inductor.The interplay between superconductivity and ferromagnetism in superconductor-ferromagnet (SF) hybrids exhibits a large variety of effects studied along the last years 1,2 . Experimental research mainly focuses on the control of the 0-π transition in the S-F-S junctions 3 and on the creation, detection, and manipulation of triplet correlations in SF hybrids [4][5][6][7][8][9] . From a fundamental point of view, the key phenomenon for the understanding of these effects is the proximity effect in SF hybrids, and how the interplay between superconducting and magnetic correlations affects their thermodynamic and transport properties. While most of theoretical and experimental investigations on SF structures deal mainly with the penetration of superconducting correlations into the F regions, it is also widely known that magnetic correlations can be induced in the superconductor via the inverse proximity effect [10][11][12][13] . If the ferromagnet is an insu- lator (FI), on the one hand, superconducting correlations are weakly suppressed at the FI-S interface and, on the other hand, a finite exchange field (h ex ) is induced at the interface and penetrates into the S region over distances of the order of the coherence length 10 . This results in a spin splitting of the density of states (DoS) of the superconductor, as observed in a number of experiments 14-17 . This spin-splitting may lead to interesting phenomena such as the absolute spin valve effect 18-20 , the magnetothermal Josephson valve 21,22 , and the enhancement of the Josephson current in SF-I-SF junctions (I stands for a conventional insulator) [23][24][25][26][27] .In this Letter we investigate the Josephson current in a mesoscopic FIS-N-FIS junction. As we show below, the presence of a normal metal instead of an insulator provides access to a rich nontrivial phenomenology which stems from the interplay of phase-tunable superconducting and magnetic correlations in the N region. The impact of magnetic correlations on the Josephson coupling is explored for two transversal magnetization directions of the FIS layers, i.e., parallel (P) and antiparallel (AP). This results in an enhancement of the critical current and in peculiar current-phase relations (CPRs). We propose realistic hybrid setups to observe these anomalous effects, and discuss how to exploit them for practical applicat...

show abstract

Andreev levels spectroscopy of topological three-terminal junctions

Cited by 14 publications

References 35 publications

Tomography of Majorana fermions with STM tips

Tomography of Majorana fermions with STM tips

A ballistic two-dimensional-electron-gas Andreev interferometer

Mesoscopic Josephson junctions with switchable current-phase relation

Contact Info

Product

Resources

About