Anisotropic structural dynamics of monolayer crystals revealed by femtosecond surface X-ray scattering
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Univ. of Southern California, Los Angeles, CA (United States)
- Univ. of Washington, Seattle, WA (United States)
- Stanford Univ., CA (United States)
- Stanford Univ., CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States). Photon Ultrafast Laser Science and Engineering Inst. (PULSE)
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Kumamoto Univ., Kumamoto (Japan)
- Stanford Univ., CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States). Photon Ultrafast Laser Science and Engineering Inst. (PULSE); SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Institute for Materials and Energy Science (SIMES)
Ultrafast X-ray scattering is one of the primary tools to track intrinsic crystallographic evolution with atomic accuracy in real time. However, its application to study nonequilibrium structural properties at the two-dimensional limit remains a long-standing challenge due to a significant reduction of diffraction volume and complexity of data analysis. Here, we report femtosecond surface X-ray diffraction in combination with crystallographic model-refinement calculations to quantify the ultrafast structural dynamics of monolayer WSe2 crystals supported on a substrate. We found the absorbed optical photon energy is preferably coupled to the in-plane lattice vibrations within one picosecond whereas the out-of-plane lattice vibration amplitude remains unchanged during the first ten picoseconds. The model-assisted fitting suggests an asymmetric intralayer spacing change upon excitation. The observed nonequilibrium anisotropic structural dynamics agrees with first-principles modelling in both real and momentum space, marking the distinct structural dynamics of monolayer crystals from their bulk counterparts.
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC02-76SF00515
- OSTI ID:
- 1532479
- Journal Information:
- Nature Photonics, Journal Name: Nature Photonics Journal Issue: 6 Vol. 13; ISSN 1749-4885
- Publisher:
- Nature Publishing GroupCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Quantum Dynamics at Scale: Ultrafast Control of Emergent Functional Materials
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conference | January 2020 |
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