Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 58: Poster Session III (Solid-liquid interfaces; Scanning probe and other methods; Electronic structure theory; Spin-orbit interaction)
O 58.51: Poster
Mittwoch, 13. März 2013, 18:15–21:45, Poster B1
Nanosecond scanning tunneling microscopy — •Shichao Yan1,2, Deung-Jang Choi1,2, and Sebastian Loth1,2 — 1Max Planck Research Group-Dynamics of Nanoelectronic Systems, Center for Free-Electron Laser Science, Hamburg — 2Max Planck Institute for Solid State Research, Stuttgart
The scanning tunneling microscope (STM) can provide very high spatial resolution down to the atomic scale. One of the usual limits of the STM technique is its limited time resolution which is typically miliseconds because of the bandwidth of the control electronics. Yet, many processes on the nanoscale occur at nanosecond speed or faster. We present the instrumentation and test of a scanning tunneling microscope system that combines sub-Kelvin operation with high-frequency electronic circuitry. Nanosecond or picosecond electric pump-probe pulses can be introduced into the tunneling junction with high fidelity to study the dynamics of the nanostructures. The design of the high bandwidth circuitry and the cooling mechanism of the semi-rigid cables will be presented. With this instrument, we have reached nanosecond time resolution while maintaining atomic spatial resolution. We apply this technique to measure the spin relaxation time of iron nanostructures on copper nitride. In principle, the electric pump-probe STM technique can also be used to study long lifetime vibrational excitations and conformational changes of molecules.