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Title: Mach-Zehnder interferometry using spin- and valley-polarized quantum Hall edge states in graphene

Confined to a two-dimensional plane, electrons in a strong magnetic field travel along the edge in one-dimensional quantum Hall channels that are protected against backscattering. These channels can be used as solid-state analogs of monochromatic beams of light, providing a unique platform for studying electron interference. Electron interferometry is regarded as one of the most promising routes for studying fractional and non-Abelian statistics and quantum entanglement via two-particle interference. However, creating an edge-channel interferometer in which electron-electron interactions play an important role requires a clean system and long phase coherence lengths. We realize electronic Mach-Zehnder interferometers with record visibilities of up to 98% using spin- and valley-polarized edge channels that copropagate along a pn junction in graphene. We find that interchannel scattering between same-spin edge channels along the physical graphene edge can be used to form beamsplitters, whereas the absence of interchannel scattering along gate-defined interfaces can be used to form isolated interferometer arms. Surprisingly, our interferometer is robust to dephasing effects at energies an order of magnitude larger than those observed in pioneering experiments on GaAs/AlGaAs quantum wells. Lastly, our results shed light on the nature of edge-channel equilibration and open up new possibilities for studying exotic electron statisticsmore » and quantum phenomena.« less
Authors:
 [1] ; ORCiD logo [2] ; ORCiD logo [3] ; ORCiD logo [4] ;  [4] ;  [5] ; ORCiD logo [2] ; ORCiD logo [6]
  1. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences
  2. Harvard Univ., Cambridge, MA (United States). Dept. of Physics
  3. Harvard Univ., Cambridge, MA (United States). Dept. of Physics; Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Physics
  4. National Inst. for Materials Science (NIMS), Tsukuba (Japan). Advanced Materials Lab.
  5. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Physics
  6. Harvard Univ., Cambridge, MA (United States). John A. Paulson School of Engineering and Applied Sciences; Harvard Univ., Cambridge, MA (United States). Dept. of Physics
Publication Date:
Grant/Contract Number:
SC0001819; DGE1144152; DMR-1231319; JP26248061; JP15K21722; JP25106006
Type:
Accepted Manuscript
Journal Name:
Science Advances
Additional Journal Information:
Journal Volume: 3; Journal Issue: 8; Journal ID: ISSN 2375-2548
Publisher:
AAAS
Research Org:
Harvard Univ., Cambridge, MA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1463899

Wei, Di S., van der Sar, Toeno, Sanchez-Yamagishi, Javier D., Watanabe, Kenji, Taniguchi, Takashi, Jarillo-Herrero, Pablo, Halperin, Bertrand I., and Yacoby, Amir. Mach-Zehnder interferometry using spin- and valley-polarized quantum Hall edge states in graphene. United States: N. p., Web. doi:10.1126/sciadv.1700600.
Wei, Di S., van der Sar, Toeno, Sanchez-Yamagishi, Javier D., Watanabe, Kenji, Taniguchi, Takashi, Jarillo-Herrero, Pablo, Halperin, Bertrand I., & Yacoby, Amir. Mach-Zehnder interferometry using spin- and valley-polarized quantum Hall edge states in graphene. United States. doi:10.1126/sciadv.1700600.
Wei, Di S., van der Sar, Toeno, Sanchez-Yamagishi, Javier D., Watanabe, Kenji, Taniguchi, Takashi, Jarillo-Herrero, Pablo, Halperin, Bertrand I., and Yacoby, Amir. 2017. "Mach-Zehnder interferometry using spin- and valley-polarized quantum Hall edge states in graphene". United States. doi:10.1126/sciadv.1700600. https://www.osti.gov/servlets/purl/1463899.
@article{osti_1463899,
title = {Mach-Zehnder interferometry using spin- and valley-polarized quantum Hall edge states in graphene},
author = {Wei, Di S. and van der Sar, Toeno and Sanchez-Yamagishi, Javier D. and Watanabe, Kenji and Taniguchi, Takashi and Jarillo-Herrero, Pablo and Halperin, Bertrand I. and Yacoby, Amir},
abstractNote = {Confined to a two-dimensional plane, electrons in a strong magnetic field travel along the edge in one-dimensional quantum Hall channels that are protected against backscattering. These channels can be used as solid-state analogs of monochromatic beams of light, providing a unique platform for studying electron interference. Electron interferometry is regarded as one of the most promising routes for studying fractional and non-Abelian statistics and quantum entanglement via two-particle interference. However, creating an edge-channel interferometer in which electron-electron interactions play an important role requires a clean system and long phase coherence lengths. We realize electronic Mach-Zehnder interferometers with record visibilities of up to 98% using spin- and valley-polarized edge channels that copropagate along a pn junction in graphene. We find that interchannel scattering between same-spin edge channels along the physical graphene edge can be used to form beamsplitters, whereas the absence of interchannel scattering along gate-defined interfaces can be used to form isolated interferometer arms. Surprisingly, our interferometer is robust to dephasing effects at energies an order of magnitude larger than those observed in pioneering experiments on GaAs/AlGaAs quantum wells. Lastly, our results shed light on the nature of edge-channel equilibration and open up new possibilities for studying exotic electron statistics and quantum phenomena.},
doi = {10.1126/sciadv.1700600},
journal = {Science Advances},
number = 8,
volume = 3,
place = {United States},
year = {2017},
month = {8}
}

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