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Title: Analysis of Scanned Probe Images for Magnetic Focusing in Graphene

Abstract

We have used cooled scanning probe microscopy (SPM) to study electron motion in nanoscale devices. The charged tip of the microscope was raster-scanned at constant height above the surface as the conductance of the device was measured. The image charge scatters electrons away, changing the path of electrons through the sample. Using this technique, we imaged cyclotron orbits that flow between two narrow contacts in the magnetic focusing regime for ballistic hBN–graphene–hBN devices. We present herein an analysis of our magnetic focusing imaging results based on the effects of the tip-created charge density dip on the motion of ballistic electrons. The density dip locally reduces the Fermi energy, creating a force that pushes electrons away from the tip. When the tip is above the cyclotron orbit, electrons are deflected away from the receiving contact, creating an image by reducing the transmission between contacts. The data and our analysis suggest that the graphene edge is rather rough, and electrons scattering off the edge bounce in random directions. However, when the tip is close to the edge, it can enhance transmission by bouncing electrons away from the edge, toward the receiving contact. Our results demonstrate that cooled SPM is a promising toolmore » to investigate the motion of electrons in ballistic graphene devices.« less

Authors:
 [1];  [2];  [3];  [3]
  1. Harvard Univ., Cambridge, MA (United States). School of Engineering and Applied Sciences
  2. Harvard Univ., Cambridge, MA (United States). Dept. of Physics
  3. Harvard Univ., Cambridge, MA (United States). School of Engineering and Applied Sciences. Dept. of Physics
Publication Date:
Research Org.:
Harvard Univ., Cambridge, MA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); US Air Force Office of Scientific Research (AFOSR); National Science Foundation (NSF)
OSTI Identifier:
1344318
Alternate Identifier(s):
OSTI ID: 1423801
Grant/Contract Number:  
FG02-07ER46422; FA9550-13-1-0211
Resource Type:
Journal Article: Published Article
Journal Name:
Journal of Electronic Materials
Additional Journal Information:
Journal Volume: 46; Journal Issue: 7; Journal ID: ISSN 0361-5235
Publisher:
Springer
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 47 OTHER INSTRUMENTATION; scanning probe microscopy theory; ballistic transport; graphene; simulation; magnetic focusing; electron trajectories

Citation Formats

Bhandari, Sagar, Lee, Gil-Ho, Kim, Philip, and Westervelt, Robert M. Analysis of Scanned Probe Images for Magnetic Focusing in Graphene. United States: N. p., 2017. Web. doi:10.1007/s11664-017-5350-y.
Bhandari, Sagar, Lee, Gil-Ho, Kim, Philip, & Westervelt, Robert M. Analysis of Scanned Probe Images for Magnetic Focusing in Graphene. United States. doi:10.1007/s11664-017-5350-y.
Bhandari, Sagar, Lee, Gil-Ho, Kim, Philip, and Westervelt, Robert M. Tue . "Analysis of Scanned Probe Images for Magnetic Focusing in Graphene". United States. doi:10.1007/s11664-017-5350-y.
@article{osti_1344318,
title = {Analysis of Scanned Probe Images for Magnetic Focusing in Graphene},
author = {Bhandari, Sagar and Lee, Gil-Ho and Kim, Philip and Westervelt, Robert M.},
abstractNote = {We have used cooled scanning probe microscopy (SPM) to study electron motion in nanoscale devices. The charged tip of the microscope was raster-scanned at constant height above the surface as the conductance of the device was measured. The image charge scatters electrons away, changing the path of electrons through the sample. Using this technique, we imaged cyclotron orbits that flow between two narrow contacts in the magnetic focusing regime for ballistic hBN–graphene–hBN devices. We present herein an analysis of our magnetic focusing imaging results based on the effects of the tip-created charge density dip on the motion of ballistic electrons. The density dip locally reduces the Fermi energy, creating a force that pushes electrons away from the tip. When the tip is above the cyclotron orbit, electrons are deflected away from the receiving contact, creating an image by reducing the transmission between contacts. The data and our analysis suggest that the graphene edge is rather rough, and electrons scattering off the edge bounce in random directions. However, when the tip is close to the edge, it can enhance transmission by bouncing electrons away from the edge, toward the receiving contact. Our results demonstrate that cooled SPM is a promising tool to investigate the motion of electrons in ballistic graphene devices.},
doi = {10.1007/s11664-017-5350-y},
journal = {Journal of Electronic Materials},
number = 7,
volume = 46,
place = {United States},
year = {Tue Feb 21 00:00:00 EST 2017},
month = {Tue Feb 21 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1007/s11664-017-5350-y

Citation Metrics:
Cited by: 1 work
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Works referenced in this record:

The electronic properties of graphene
journal, January 2009

  • Castro Neto, A. H.; Guinea, F.; Peres, N. M. R.
  • Reviews of Modern Physics, Vol. 81, Issue 1, p. 109-162
  • DOI: 10.1103/RevModPhys.81.109

The rise of graphene
journal, March 2007

  • Geim, A. K.; Novoselov, K. S.
  • Nature Materials, Vol. 6, Issue 3, p. 183-191
  • DOI: 10.1038/nmat1849