Directly photoexcited Dirac and Weyl fermions in ZrSiS and NbAs
- Santa Clara Univ., Santa Clara, CA (United States)
- Princeton Univ., NJ (United States)
- Max Planck Inst. of Microstructure Physics, Halle (Germany)
- Academy of Sciences of Moldova, Chisinau (Moldova)
- Max Planck Inst. for Solid State Research, Stuttgart (Germany); Ludwig Maximilian Univ., Munich (Germany)
- Okinawa Inst. of Science and Technology Graduate Univ., Okinawa (Japan); Central Univ. of Karnataka, Kadaganchi (India)
- Okinawa Inst. of Science and Technology Graduate Univ., Okinawa (Japan)
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
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.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); National Science Foundation (NSF); Army Research Office (ARO)
- Grant/Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1542341
- Journal Information:
- Applied Physics Letters, Vol. 113, Issue 22; ISSN 0003-6951
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Dynamically Induced Excitonic Instability in Pumped Dirac Materials
|
journal | December 2019 |
The role of delocalized chemical bonding in square-net-based topological semimetals | text | January 2020 |
Transient Drude Response Dominates Near-Infrared Pump-Probe Reflectivity in Nodal-Line Semimetals ZrSiS and ZrSiSe | preprint | January 2020 |
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