This talk covers our two recent results: 1) realization of the quantum Hall-based SQUID in side-gated samples and 2) observation of the chiral Andreev edge states – hybrid electron/hole single particle modes propagating along the superconductor - quantum Hall interfaces.
1) We have developed graphene Josephson junctions with self-aligned side gates, which enable full control over the electrostatic potential near the sample edges. The gates allow us to tune the local electron density in a wide range, in particular inducing counterpropagating quantum Hall edge states along either side gate. The close spacing between these states allows them to efficiently couple through Andreev reflections and carry supercurrent. When both side gates are applied, superconducting channels are created on both sides of the junction, thereby realizing a gate-tunable quantum Hall-based SQUID.
2) We observe direct signatures of chiral Andreev edge states (CAES) – single particle modes running along the superconductor - quantum Hall interfaces. Semi-classically, the CAES can be interpreted as a result of multiple Andreev reflections of a single electron/hole skipping along the interface. Experimentally, we observe fluctuations of the signal propagating along the superconducting contact and interpret them in terms of interference between the CAES.
**Transport measurements conducted by L.Z., E.G.A., and A.S. were supported by the DOE Award No. de-sc 0002765. Lithographic fabrication and samples characterization was performed by L.Z., M.-T. W., and A.S. with the support of NSF award DMR-1743907. The measurement setup was developed by A.W.D., T.L., and G.F. with the support of ARO Award W911NF-16-1-0122. Numerical simulations conducted by A.B. and H.U.B. were supported by the DOE Award No. de-sc0005237. H.L. and F.A. acknowledge the ARO Award W911NF-16-1- 0132. K.W. and T.T. acknowledge support from JSPS KAKENHI Grant Number JP15K21722.
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Presenters
Gleb Finkelstein
Duke University
Authors
Andrew Seredinski
Wentworth Institute of Technology
Wentworth Inst of Tech
Duke University
Lingfei Zhao
Duke University
Ethan Arnault
Duke University
Alexey Bondarev
Duke University
Anne M Draelos
Duke University
Trevyn Larson
Duke University
Ming Tso Wei
Duke University
Takashi Taniguchi
National Institute for Materials Science
National Institute for Materials Science, Japan
National Institure for Materials Science
Advanced Materials Laboratory, National Institute for Materials Science
NIMS
National Institute of Materials Science
National Institute for Materials Science (NIMS)
International Center for Materials Nanoarchitectonics, National Institute for Materials Science
National Institute for Materials Science,1-1 Namiki
National Institute of Material Science
National Institute for Materials Science, Tsukuba, Japan
International Center for Materials Nanoarchitectonics, NIMS
Research Center for Functional Materials, National Institute for Materials Science
National Institute of Materials Science, Tsukuba, Japan
National Institude for Materials Science
International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-0044, Japan
International Center for Materials Nanoarchitectonics, National Institute for Materials
NIMS - Japan
National Institute for Materials Science ,Japan
National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan
National Institute for Material Science
National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
National Institute for Material Science Japan
8International Center for Materials Nanoarchitectonics
NIMS Tsukuba
National Institute for Materials Science: Namiki, Tsukuba, Ibaraki, JP
National Institue for Material Science
National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan
Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Research Center for Functional Materials, National In
Research Center for Functional Materials, Japan
Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
International Center for Material Nanoarchitectonics, National Institute for Materials Science
International Center for Materials Nanoarchitectonics
NIMS Suguba
NIMS, Tsukuba, Japan
National Cheng Kung University
National Institute for Materials Science, Namiki 1-1, Tsukuba, 305-0044, Ibaraki, Japan
National institute of material science
Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
Advanced Materials Laboratory, NIMS
National Institute for Materials Science, International Center for Materials Nanoarchitectonics
National Institute of Material Science, Japan
Tsukuba, National Institute for Materials Science
Kenji Watanabe
National Institute for Materials Science
National Institute for Materials Science, Japan
National Institure for Materials Science
Advanced Materials Laboratory, National Institute for Materials Science
NIMS
National Institute of Materials Science
National Institute for Materials Science (NIMS)
Research Center for Functional Materials, National Institute for Materials Science
National Institute for Materials Science,1-1 Namiki
National Institute of Material Science
National Institute for Materials Science, Tsukuba, Japan
Research Center for Functional Materials, NIMS
National Institute of Materials Science, Tsukuba, Japan
National Institude for Materials Science
National Institute for Materials Science, Tsukuba, Ibaraki, Japan
Research Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan
International Center for Materials Nanoarchitectonics, National Institute for Materials
NIMS - Japan
National Institute for Materials Science ,Japan
National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan
National Institute for Material Science
National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
National Institute for Material Science Japan
NIMS Tsukuba
National Institute for Materials Science, Research Center for Functional Materials, Japan
Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
National Institute for Materials Science: Namiki, Tsukuba, Ibaraki, JP
National Institue for Material Science
National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan
Materials, NIMS
Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Research Center for Functional Materials, National In
Research Center for Functional Materials, Japan
International Center for Materials Nanoarchitectonics, National Institute for Materials Science
International Center for Materials nanoarchtectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
NIMS Suguba
NIMS, Tsukuba, Japan
National Institute for Materials Science, Namiki 1-1, Tsukuba, 305-0044, Ibaraki, Japan
National institute of material science
Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
Advanced Materials Laboratory, NIMS
Research Center for Functional Materials, National Institute for Materials Science, Ibaraki, Japan
National Institute for Materials Science, Research Center for Functional Materials
