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Title: Directly photoexcited Dirac and Weyl fermions in ZrSiS and NbAs

Abstract

We report ultrafast optical measurements of the Dirac line-node semimetal ZrSiS and the Weyl semimetal NbAs, using mid-infrared pump photons from 86 meV to 500 meV to directly excite Dirac and Weyl fermions within the linearly dispersing bands. In NbAs, the photoexcited Weyl fermions initially form a non-thermal distribution, signified by a brief spike in the differential reflectivity whose sign is controlled by the relative energy of the pump and probe photons. In ZrSiS, electron-electron scattering rapidly thermalizes the electrons, and the spike is not observed. Subsequently, hot carriers in both materials cool within a few picoseconds. This cooling, as seen in the two materials' differential reflectivity, differs in sign, shape, and timescale. Nonetheless, we find that it may be described in a simple model of thermal electrons, without free parameters. The electronic cooling in ZrSiS is particularly fast, which may make the material useful for optoelectronic applications.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3];  [1];  [4];  [5];  [6];  [1]; ORCiD logo [7];  [8];  [4];  [3]
  1. Santa Clara Univ., Santa Clara, CA (United States)
  2. Princeton Univ., NJ (United States)
  3. Max Planck Inst. of Microstructure Physics, Halle (Germany)
  4. Academy of Sciences of Moldova, Chisinau (Moldova)
  5. Max Planck Inst. for Solid State Research, Stuttgart (Germany); Ludwig Maximilian Univ., Munich (Germany)
  6. Okinawa Inst. of Science and Technology Graduate Univ., Okinawa (Japan); Central Univ. of Karnataka, Kadaganchi (India)
  7. Okinawa Inst. of Science and Technology Graduate Univ., Okinawa (Japan)
  8. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC); National Science Foundation (NSF); Army Research Office (ARO)
OSTI Identifier:
1542341
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 113; Journal Issue: 22; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

Citation Formats

Weber, Chris P., Schoop, Leslie M., Parkin, Stuart S. P., Newby, Robert C., Nateprov, Alex, Lotsch, Bettina, Mariserla, Bala Murali Krishna, Kim, J. Matthew, Dani, Keshav M., Bechtel, Hans A., Arushanov, Ernest, and Ali, Mazhar. Directly photoexcited Dirac and Weyl fermions in ZrSiS and NbAs. United States: N. p., 2018. Web. doi:10.1063/1.5055207.
Weber, Chris P., Schoop, Leslie M., Parkin, Stuart S. P., Newby, Robert C., Nateprov, Alex, Lotsch, Bettina, Mariserla, Bala Murali Krishna, Kim, J. Matthew, Dani, Keshav M., Bechtel, Hans A., Arushanov, Ernest, & Ali, Mazhar. Directly photoexcited Dirac and Weyl fermions in ZrSiS and NbAs. United States. doi:10.1063/1.5055207.
Weber, Chris P., Schoop, Leslie M., Parkin, Stuart S. P., Newby, Robert C., Nateprov, Alex, Lotsch, Bettina, Mariserla, Bala Murali Krishna, Kim, J. Matthew, Dani, Keshav M., Bechtel, Hans A., Arushanov, Ernest, and Ali, Mazhar. Mon . "Directly photoexcited Dirac and Weyl fermions in ZrSiS and NbAs". United States. doi:10.1063/1.5055207.
@article{osti_1542341,
title = {Directly photoexcited Dirac and Weyl fermions in ZrSiS and NbAs},
author = {Weber, Chris P. and Schoop, Leslie M. and Parkin, Stuart S. P. and Newby, Robert C. and Nateprov, Alex and Lotsch, Bettina and Mariserla, Bala Murali Krishna and Kim, J. Matthew and Dani, Keshav M. and Bechtel, Hans A. and Arushanov, Ernest and Ali, Mazhar},
abstractNote = {We report ultrafast optical measurements of the Dirac line-node semimetal ZrSiS and the Weyl semimetal NbAs, using mid-infrared pump photons from 86 meV to 500 meV to directly excite Dirac and Weyl fermions within the linearly dispersing bands. In NbAs, the photoexcited Weyl fermions initially form a non-thermal distribution, signified by a brief spike in the differential reflectivity whose sign is controlled by the relative energy of the pump and probe photons. In ZrSiS, electron-electron scattering rapidly thermalizes the electrons, and the spike is not observed. Subsequently, hot carriers in both materials cool within a few picoseconds. This cooling, as seen in the two materials' differential reflectivity, differs in sign, shape, and timescale. Nonetheless, we find that it may be described in a simple model of thermal electrons, without free parameters. The electronic cooling in ZrSiS is particularly fast, which may make the material useful for optoelectronic applications.},
doi = {10.1063/1.5055207},
journal = {Applied Physics Letters},
number = 22,
volume = 113,
place = {United States},
year = {2018},
month = {11}
}

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Works referenced in this record:

X-Ray Interactions: Photoabsorption, Scattering, Transmission, and Reflection at E = 50-30,000 eV, Z = 1-92
journal, July 1993

  • Henke, B. L.; Gullikson, E. M.; Davis, J. C.
  • Atomic Data and Nuclear Data Tables, Vol. 54, Issue 2, p. 181-342
  • DOI: 10.1006/adnd.1993.1013