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Title: Inter-Landau-level Andreev Reflection at the Dirac Point in a Graphene Quantum Hall State Coupled to a NbSe 2 Superconductor

Abstract

Superconductivity and quantum Hall effect are distinct states of matter occurring in apparently incompatible physical conditions. Recent theoretical developments suggest that the coupling of quantum Hall effect with a superconductor can provide a fertile ground for realizing exotic topologi- cal 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.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Pennsylvania State Univ., University Park, PA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1489113
Alternate Identifier(s):
OSTI ID: 1466437; OSTI ID: 1489110
Grant/Contract Number:  
SC0005042; 2016YFA0401003
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 121; Journal Issue: 8; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; graphene; Andreev effect; quantum Hall effect; superconductivity

Citation Formats

Sahu, Manas Ranjan, Liu, Xin, Paul, Arup Kumar, Das, Sourin, Raychaudhuri, Pratap, Jain, J. K., and Das, Anindya. Inter-Landau-level Andreev Reflection at the Dirac Point in a Graphene Quantum Hall State Coupled to a NbSe2 Superconductor. United States: N. p., 2018. Web. doi:10.1103/PhysRevLett.121.086809.
Sahu, Manas Ranjan, Liu, Xin, Paul, Arup Kumar, Das, Sourin, Raychaudhuri, Pratap, Jain, J. K., & Das, Anindya. Inter-Landau-level Andreev Reflection at the Dirac Point in a Graphene Quantum Hall State Coupled to a NbSe2 Superconductor. United States. doi:10.1103/PhysRevLett.121.086809.
Sahu, Manas Ranjan, Liu, Xin, Paul, Arup Kumar, Das, Sourin, Raychaudhuri, Pratap, Jain, J. K., and Das, Anindya. Wed . "Inter-Landau-level Andreev Reflection at the Dirac Point in a Graphene Quantum Hall State Coupled to a NbSe2 Superconductor". United States. doi:10.1103/PhysRevLett.121.086809. https://www.osti.gov/servlets/purl/1489113.
@article{osti_1489113,
title = {Inter-Landau-level Andreev Reflection at the Dirac Point in a Graphene Quantum Hall State Coupled to a NbSe2 Superconductor},
author = {Sahu, Manas Ranjan and Liu, Xin and Paul, Arup Kumar and Das, Sourin and Raychaudhuri, Pratap and Jain, J. K. and Das, Anindya},
abstractNote = {Superconductivity and quantum Hall effect are distinct states of matter occurring in apparently incompatible physical conditions. Recent theoretical developments suggest that the coupling of quantum Hall effect with a superconductor can provide a fertile ground for realizing exotic topologi- cal 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.},
doi = {10.1103/PhysRevLett.121.086809},
journal = {Physical Review Letters},
issn = {0031-9007},
number = 8,
volume = 121,
place = {United States},
year = {2018},
month = {8}
}

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Works referenced in this record:

Electric Field Effect in Atomically Thin Carbon Films
journal, October 2004