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Title: Super-geometric electron focusing on the hexagonal Fermi surface of PdCoO 2

Abstract

Geometric electron optics may be implemented in solids when electron transport is ballistic on the length scale of a device. Currently, this is realized mainly in 2D materials characterized by circular Fermi surfaces. Here we demonstrate that the nearly perfectly hexagonal Fermi surface of PdCoO 2 gives rise to highly directional ballistic transport. We probe this directional ballistic regime in a single crystal of PdCoO 2 by use of focused ion beam (FIB) micro-machining, defining crystalline ballistic circuits with features as small as 250 nm. The peculiar hexagonal Fermi surface naturally leads to enhanced electron self-focusing effects in a magnetic field compared to circular Fermi surfaces. This super-geometric focusing can be quantitatively predicted for arbitrary device geometry, based on the hexagonal cyclotron orbits appearing in this material. These results suggest a novel class of ballistic electronic devices exploiting the unique transport characteristics of strongly faceted Fermi surfaces.

Authors:
 [1]; ORCiD logo [2];  [3];  [4];  [5];  [5];  [6]; ORCiD logo [1]; ORCiD logo [4]
  1. Max Planck Inst. for Chemical Physics of Solids, Dresden (Germany); Univ. of St. Andrews, Scotland (United Kingdom)
  2. Stanford Univ., CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  3. Stanford Univ., CA (United States)
  4. Max Planck Inst. for Chemical Physics of Solids, Dresden (Germany); Ecole Polytechnique Federale Lausanne (Switzlerland)
  5. Max Planck Inst. for Chemical Physics of Solids, Dresden (Germany)
  6. SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., CA (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Stanford Univ., CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21); European Research Council (ERC); Engineering and Physical Sciences Research Council (EPSRC); National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
OSTI Identifier:
1577774
Alternate Identifier(s):
OSTI ID: 1595724
Grant/Contract Number:  
AC02-76SF00515; 715730; EP/I007002/1; AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 10; Journal Issue: 1; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Science and Technology - Other Topics

Citation Formats

Bachmann, Maja D., Sharpe, Aaron L., Barnard, Arthur W., Putzke, Carsten, König, Markus, Khim, Seunghyun, Goldhaber-Gordon, David, Mackenzie, Andrew P., and Moll, Philip J. W. Super-geometric electron focusing on the hexagonal Fermi surface of PdCoO2. United States: N. p., 2019. Web. doi:10.1038/s41467-019-13020-9.
Bachmann, Maja D., Sharpe, Aaron L., Barnard, Arthur W., Putzke, Carsten, König, Markus, Khim, Seunghyun, Goldhaber-Gordon, David, Mackenzie, Andrew P., & Moll, Philip J. W. Super-geometric electron focusing on the hexagonal Fermi surface of PdCoO2. United States. doi:10.1038/s41467-019-13020-9.
Bachmann, Maja D., Sharpe, Aaron L., Barnard, Arthur W., Putzke, Carsten, König, Markus, Khim, Seunghyun, Goldhaber-Gordon, David, Mackenzie, Andrew P., and Moll, Philip J. W. Fri . "Super-geometric electron focusing on the hexagonal Fermi surface of PdCoO2". United States. doi:10.1038/s41467-019-13020-9. https://www.osti.gov/servlets/purl/1577774.
@article{osti_1577774,
title = {Super-geometric electron focusing on the hexagonal Fermi surface of PdCoO2},
author = {Bachmann, Maja D. and Sharpe, Aaron L. and Barnard, Arthur W. and Putzke, Carsten and König, Markus and Khim, Seunghyun and Goldhaber-Gordon, David and Mackenzie, Andrew P. and Moll, Philip J. W.},
abstractNote = {Geometric electron optics may be implemented in solids when electron transport is ballistic on the length scale of a device. Currently, this is realized mainly in 2D materials characterized by circular Fermi surfaces. Here we demonstrate that the nearly perfectly hexagonal Fermi surface of PdCoO2 gives rise to highly directional ballistic transport. We probe this directional ballistic regime in a single crystal of PdCoO2 by use of focused ion beam (FIB) micro-machining, defining crystalline ballistic circuits with features as small as 250 nm. The peculiar hexagonal Fermi surface naturally leads to enhanced electron self-focusing effects in a magnetic field compared to circular Fermi surfaces. This super-geometric focusing can be quantitatively predicted for arbitrary device geometry, based on the hexagonal cyclotron orbits appearing in this material. These results suggest a novel class of ballistic electronic devices exploiting the unique transport characteristics of strongly faceted Fermi surfaces.},
doi = {10.1038/s41467-019-13020-9},
journal = {Nature Communications},
number = 1,
volume = 10,
place = {United States},
year = {2019},
month = {11}
}

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