Abstract
Realizing fast energy dissipation in crystalline materials over macroscopic length scales is critical for energy-efficient devices and applications toward a carbon-neutral society but is usually dominated by electron-lattice interactions that cap the energy dissipation at the phonon velocity. Going beyond this velocity has been the focus of many studies, and the physical limit is the Fermi velocity where the energy is predominantly carried away by electrons throughout the materials. However, whether and how the Fermi velocity can be reached over macroscopic distances experimentally remain largely elusive. Here we show ultrafast energy dissipation at the Fermi velocity in the magnetocaloric metal LaFe10.6Co1.0Si1.4. Using time-resolved powder x-ray diffraction, we observe negative thermal expansion of the lattice throughout the micron-sized crystals in less than 600 fs with an incident optical fluence higher than 8 Jcm-2. The ultrafast timescale is in sharp contrast to the normal energy dissipation and shows the existence of a macroscopic momentum-relaxing electron mean free path immediately after the optical excitation. Our findings open a different regime in energy dissipation and demonstrate the possibility of manipulating macroscopic material properties by strong optical pulses.
Original language | English (US) |
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Article number | 134323 |
Journal | Physical Review B |
Volume | 110 |
Issue number | 13 |
DOIs | |
State | Published - Oct 1 2024 |
Externally published | Yes |
Funding
The work conducted at the Institute of Metal Research was supported by the Ministry of Science and Technology of China (Grants No. 2021YFB3501201 and No. 2022YFE0109900), the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences (Grant No. ZDBS-LY-JSC002), and the International Partner Program of the Chinese Academy of Sciences (Grant No. 174321KYSB20200008). The work conducted at the Institute of Physics was supported by the Ministry of Science and Technology of China (Grant No. 2021YFB3501202) and the National Natural Science Foundation of China (Grants No. U1832219 and No. 52088101). Y. Chen and M.J.B. were supported by the Northwestern University (NU) Institute of Catalysis in Energy Processes, which is funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award No. DE-FG02-03ER15457. O.S. was supported by Grants-in-Aid for Scientific Research (C), Grant No. 18K04868. The analysis and interpretation of the experiment at SACLA were supported in part by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. K.J.H. was supported by Laboratory Directed Research and Development (LDRD) funding from Argonne National Laboratory, provided by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-06CH11357. We acknowledge beam time awarded by SACLA (Proposals No. 2019A8092 and No. 2019B8077). Y. Cao also thanks I. K. Robinson for helpful discussions.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics