• DOI:10.1038/s41586-020-03049-y
• Corpus ID: 230796384

Single-defect phonons imaged by electron microscopy

@article{Yan2021SingledefectPI,
  title={Single-defect phonons imaged by electron microscopy},
  author={Xingxu Yan and Cheng-yan Liu and Chaitanya A Gadre and Lei Gu and Toshihiro Aoki and Tracy Clark Lovejoy and Niklas Dellby and Ondrej L. Krivanek and Darrell G. Schlom and Ruqian Wu and Xiaoqing Pan},
  journal={Nature},
  year={2021},
  volume={589},
  pages={65-69}
}

• Xingxu Yan, Cheng-yan Liu, +8 authors Xiaoqing Pan
• Published 1 January 2021
• Physics, Materials Science
• Nature

Crystal defects affect the thermal and heat-transport properties of materials by scattering phonons and modifying phonon spectra 1 – 8 . To appreciate how imperfections in solids influence thermal conductivity and diffusivity, it is thus essential to understand phonon–defect interactions. Sophisticated theories are available to explore such interactions, but experimental validation is limited because most phonon-detecting spectroscopic methods do not reach the high spatial resolution needed to resolve local vibrational spectra near individual defects. Here we demonstrate that space- and angle-resolved vibrational spectroscopy in a transmission electron microscope makes it possible to map the vibrational spectra of individual crystal defects. We detect a red shift of several millielectronvolts in the energy of acoustic vibration modes near a single stacking fault in cubic silicon carbide, together with substantial changes in their intensity, and find that these changes are confined to within a few nanometres of the stacking fault. These observations illustrate that the capabilities of a state-of-the-art transmission electron microscope open the door to the direct mapping of phonon propagation around defects, which is expected to provide useful guidance for engineering the thermal properties of materials. State-of-the-art electron energy-loss spectroscopy in a transmission electron microscope maps the detailed phonon spectra of single defects in silicon carbide