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

Manas Ranjan Sahu, Xin Liu, Arup Kumar Paul, Sourin Das, Pratap Raychaudhuri, J. K. Jain, Anindya Das

Research output: Contribution to journalArticle

9 Scopus citations

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.

Original languageEnglish (US)
Article number086809
JournalPhysical review letters
Volume121
Issue number8
DOIs
StatePublished - Aug 24 2018

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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