Speaker
Description
Scanning Tunneling Microscopy (STM) atomically resolved 2D-silica in both, the amorphous [1] and the crystalline state, leading to a structural comparison of the two phases [2]. Resolving dynamic changes in 2D network structures can give indications for the fundamental processes at the atomic scale occurring during glass-transformation.
With the aim of monitoring dynamic processes during the temperature induced change of the network structure, we design a variable temperature high-speed STM. A temperature ramp from 4 to 1500 K is enabled by a continuous-flow cryostat and a sample stage heated by electron bombardment. Thermal drift is reduced due to the symmetric setup of the microscope.
For higher frame rates, a spiral scan geometry will be applied, which represents a monotonic continuous function of the angle for the radius without points of inflection nor crossing of lines. The scan is realized with a combination of a conventional STM control unit and custom made high-speed electronics.
Due to the high data throughput, programs are needed, which automatically detect atom and ring-center positions in the recorded STM images.
We hope to clarify important structural steps in oxide network structures at so far with STM unrivaled time scales.
References
[1] L. Lichtenstein, et al., Angewandte Chemie International Edition 51 (2) (2012) 404-407.
[2] L. Lichtenstein, M. Heyde, H.-J. Freund, The Journal of Physical Chemistry C 116 (38) (2012) 20426-20432.
