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GIMS Colloquium: What Limits the Time Resolution of Properties Measured by Atomic Force Microscopy?

By Stephan Addo posted 04-20-2021 12:35

  

American Physical Society, Topical Group on Instrumentation and Measurement Science
(APS GIMS) Colloquium
Friday, May 14, 2021, 3 pm eastern time

"What limits the time resolution of properties measured by Atomic Force Microscopy?"
Presented by Peter Grütter (McGill University) and Zeno Schumacher (ETH Zurich)

[SEMINAR LINK]

Grütter Abstract:
It is well-established that Atomic Force Microscopy (AFM) can determine the atomic structure of surfaces and molecules. I will give an overview of some of current research aimed at achieving and measuring properties with ultrafast temporal resolution using AFM. This opens the door to understanding charge dynamics at the relevant fundamental time and length scale on surfaces or in molecules, and in particular the role of defects.

Grütter CV
Peter Grütter is a James McGill Professor of Physics at McGill University, Fellow of the Royal Society of Canada, Fellow of the American Physical Society, and Scientific Director and founder of the McGill Nanotools Facility. He received his PhD in Physics from the University of Basel in 1989 and joined McGill University in 1994 after stays at IBM Research in California and Switzerland. His group works on developing scanning probe microscopy based tools and methods and applying them to problems in nanoscience and technology as well as to neuroscience.

Schumacher Abstract:
Recent technical advances in the field of atomic force microscopy have shown the potential to resolve dynamics in the ps range by measuring light induced forces with nanometer spatial resolution. The high force-sensitivity of atomic force microscopy (AFM) allows to resolve small variations in local optical induced forces and to decouple the probe volume from the focal size of the illumination spot. We will present how we measure the picosecond photocarrier decay in lt-GaAs as an example of a pump-probe style measurement, as a gateway to carrier dynamics in the picosecond range with non-contact AFM. Furthermore, we will present our effort to advance the time resolution down to the fs scale. This is achieved by measuring forces due to the light induced second order polarization in lithium niobate and 2D systems with no inversion symmetric such as MoSe2.

Schumacher CV
Zeno Schumacher is an ETH Fellow currently working on attosecond electron dynamics in solid state samples. During his PhD at McGill University, he developed measurement techniques to achieve ultrafast time resolution in atomic force microscopy. Picosecond electron dynamics measured by scanning probe microscopy, down to femtosecond nonlinear effects in bulk and 2D materials were demonstrated. In 2017, he joined the Ultrafast Laser Physics group of Prof. Ursula Keller at ETH Zürich and was awarded an ETH Zurich Postdoctoral Fellowship.


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