Interference of chiral Andreev edge states

Zhao, Lingfei; Arnault, Ethan G.; Bondarev, Alexey; Seredinski, Andrew; Larson, Trevyn F. Q.; Draelos, Anne; Li, Hengming; Watanabe, Kenji; Taniguchi, Takashi; Amet, François; Baranger, Harold U.; Finkelstein, Gleb

doi:10.1038/s41567-020-0898-5

Cited by 62 publications

(81 citation statements)

References 38 publications

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“…It is worth pointing out that our single-channel results also apply to the case of a Hall bar made of graphene [4,8,9], provided only the lowest Landau level is occupied and the Fermi energy is larger than the superconducting gap so the Dirac point physics [36] is not involved. We have also checked that the addition of a small Zeeman term to the Hall bar Hamiltonian does not affect the Fraunhofer patterns provided the Landau levels of both spins are occupied and the Zeeman splitting is much smaller than the level spacing δε, as assumed throughout the present work.…”

Section: Conclusion and Final Remarksmentioning

confidence: 78%

“…What might have been seen as a bold question has now become a concrete and tangible possibility [2]. Experimental groups have recently managed to make sufficiently transparent contacts between superconductors and quantum Hall states [3][4][5][6], not only enabling the measurement of a supercurrent [4,7,8], but also establishing the existence of the so called chiral Andreev edge state [9], a one-way hybrid electron-hole mode that propagates along these interfaces [10]. The electron-hole cyclotron orbits in the semiclassical regime were also recently imaged in a focusing experiment [11].…”

Section: Introductionmentioning

confidence: 99%

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Majorana fermions on the quantum Hall edge

Gavensky

Usaj

Balseiro

2020

Phys. Rev. Research

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Superconductivity and the quantum Hall effect are considered to be two cornerstones of condensed matter physics. The realization of hybrid structures where these two effects coexist has recently become an active field of research. In this work, we study a Josephson junction where a central region in the quantum Hall regime is proximitized with superconductors that can be driven to a topological phase with an external Zeeman field. In this regime, the Majorana modes that emerge at the ends of each superconducting lead couple to the chiral quantum Hall edge states. This produces distinguishable features in the Andreev levels and Fraunhofer patterns that could help in detecting not only the topological phase transition but also the spin degree of freedom of these exotic quasiparticles. The current phase relation and the spectral properties of the junction throughout the topological transition are fully described by a numerical tight-binding calculation. In pursuance of the understanding of these results, we develop a low-energy spinful model that captures the main features of the numerical transport simulations in the topological phase.

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Section: Conclusion and Final Remarksmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Majorana fermions on the quantum Hall edge

Gavensky

Usaj

Balseiro

2020

Phys. Rev. Research

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“…With further study in the fractional quantum Hall regime, this graphene platform gives new opportunities for anyon physics in QH interferometers, potentially extendable to time-resolved electron quantum optics experiments 3 . Besides, the recent advances in coupling graphene QH edge channels with superconductivity 45 – 47 may lead to a variety of novel interferometry devices 48 in which proximity-induced topological superconductivity could be intertwined with QH interferometry for readout or braiding schemes. Such perspectives could in turn open alternative pathways for quantum-information processing of topological excitations 49 .…”

Section: Discussionmentioning

confidence: 99%

A tunable Fabry–Pérot quantum Hall interferometer in graphene

et al. 2021

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Electron interferometry with quantum Hall edge channels in semiconductor heterostructures can probe and harness the exchange statistics of anyonic excitations. However, charging effects present in semiconductors often obscured the Aharonov-Bohm interference in quantum Hall interferometers and make advanced charge screening strategies necessary. Here, we show that high-mobility monolayer graphene constitutes an alternative material system, not affected by charging effects, to perform Fabry-Pérot quantum Hall interferometry in the integer quantum Hall regime. In devices equipped with gate-tunable quantum point contacts acting on the edge channels of the zeroth Landau level, we observe high-visibility Aharonov-Bohm interference widely tunable through electrostatic gating or magnetic field, in agreement with theory. A coherence length of 10 μm at a temperature of 0.02 K allows us to further achieve coherently-coupled double Fabry-Pérot interferometry. In future, quantum Hall interferometry with graphene devices may enable investigations of anyonic excitations in fractional quantum Hall states.

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“…This field scale is advantageous for the graphene ν ¼ 1 state, which is readily attainable in clean samples at fields much lower than 7 T, and is stabilized by a large in-plane field because it is a spinpolarized state [110]. Nearly transparent contacts have been made between superconducting MoRe (H c2 ∼ 10 T) and graphene in experiments designed specifically to study the interface between superconductors and quantum-Hall edge states (including the ν ¼ 1 state) [111,112]. Higher out-ofplane critical fields could be attained by using NbN or NbTiN, both of which have been used to make contact to graphene [113,114] and have H c2 exceeding 10 T, or even by integrating a layered van der Waals superconductor such as FeSe x Te 1−x , which can have H c2 in excess of 28 T at T ¼ 0 [115].…”

Section: Electrical Detection Of Chiral Majorana Edge Modes In Nonmentioning

confidence: 99%

Electrical Probes of the Non-Abelian Spin Liquid in Kitaev Materials

et al. 2020

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Recent thermal-conductivity measurements evidence a magnetic-field-induced non-Abelian spin-liquid phase in the Kitaev material α-RuCl 3. Although the platform is a good Mott insulator, we propose experiments that electrically probe the spin liquid's hallmark chiral Majorana edge state and bulk anyons, including their exotic exchange statistics. We specifically introduce circuits that exploit interfaces between electrically active systems and Kitaev materials to "perfectly" convert electrons from the former into emergent fermions in the latter-thereby enabling variations of transport probes invented for topological superconductors and fractional quantum-Hall states. Along the way, we resolve puzzles in the literature concerning interacting Majorana fermions, and also develop an anyon-interferometry framework that incorporates nontrivial energy-partitioning effects. Our results illuminate a partial pathway toward topological quantum computation with Kitaev materials.

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Interference of chiral Andreev edge states

Cited by 62 publications

References 38 publications

Majorana fermions on the quantum Hall edge

Majorana fermions on the quantum Hall edge

A tunable Fabry–Pérot quantum Hall interferometer in graphene

Electrical Probes of the Non-Abelian Spin Liquid in Kitaev Materials

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