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Inter-Landau-level Andreev Reflection at the Dirac Point in a Graphene Quantum Hall State Coupled to a NbSe2 Superconductor

Sahu, Manas Ranjan and Liu, Xin and Paul, Arup Kumar and Das, Sourin and Raychaudhuri, Pratap and Jain, J K and Das, Anindya (2018) Inter-Landau-level Andreev Reflection at the Dirac Point in a Graphene Quantum Hall State Coupled to a NbSe2 Superconductor. In: PHYSICAL REVIEW LETTERS, 121 (8).

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Official URL: http://dx.doi.org/ 10.1103/PhysRevLett.121.086809

Abstract

Superconductivity and the quantum Hall effect are distinct states of matter occurring in apparently incompatible physical conditions. Recent theoretical developments suggest that the coupling of the quantum Hall effect with a superconductor can provide fertile ground for realizing exotic topological excitations such as non-Abelian Majorana fermions or Fibonacci particles. As a step toward that goal, we report observation of Andreev reflection at the junction of a quantum Hall edge state in a single layer graphene and a quasi-two-dimensional niobium diselenide (NbSe2) superconductor. Our principal finding is the observation of an anomalous finite-temperature conductance peak located precisely at the Dirac point, providing a definitive evidence for inter-Landau-level Andreev reflection in a quantum Hall system. Our observations are well supported by detailed numerical simulations, which offer additional insight into the role of the edge states in Andreev physics. This study paves the way for investigating analogous Andreev reflection in a fractional quantum Hall system coupled to a superconductor to realize exotic quasiparticles.

Item Type: Journal Article
Publication: PHYSICAL REVIEW LETTERS
Publisher: AMER PHYSICAL SOC
Additional Information: Copy right for this article belong to AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 12 Sep 2018 15:17
Last Modified: 12 Sep 2018 15:17
URI: http://eprints.iisc.ac.in/id/eprint/60655

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