New Article in 'Physical Review Letters': Launching Coherent Acoustic Phonon Wave Packets with Local Femtosecond Coulomb Forces

August 18, 2022 /

Summary: 

Terahertz light can induce femtosecond force pulses on surfaces when it is focused onto the tip of a scanning tunneling microscope. The force pulses act as a “nano hammer” that launches coherent acoustic phonon wave packets into the material.

Typically, ultrafast lasers are used to excite acoustic phonons in materials by rapid heating of micrometer-sized areas. By contrast, the terahertz-induced phonon excitation uses the Coulomb interaction between tip and material surface. It doesn’t require heating and can be localized to a few nanometers.

Buried interfaces and defects reflect the phonon wave packets, creating a detectable beating of the surface. This enables depth-sensitive phonon nanoscopy akin to sonar on the nanometer scale and highlights the possibility of coherent control of acoustic phonons at the atomic scale.

Link to the article

  • Shaoxiang Sheng1
  • Anne-Catherine Oeter1
  • Mohamad Abdo1,2
  • Kurt Lichtenberg1
  • Mario Hentschel3
  • Sebastian Loth1,2
  • 1University of Stuttgart, Institute for Functional Matter and Quantum Technologies, 70569 Stuttgart, Germany
  • 2Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
  • 3University of Stuttgart, 4th Physics Institute and Research Center SCoPE, 70569 Stuttgart, Germany

 

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