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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 78: Scanning Probe Techniques I: Method development (joint session O/CPP)

CPP 78.9: Vortrag

Mittwoch, 18. März 2020, 17:00–17:15, TRE Ma

Development of a Variable-Temperature High-Speed Scanning Tunneling Microscope — •Zechao Yang, Leonard Gura, Jens Hartmann, Heinz Junkes, William Kirstädter, Patrik Marschalik, Markus Heyde, and Hans-Joachim Freund — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany

Scanning probe microscopy allows for resolving the atomic structure of crystalline and vitreous thin oxide films on metal substrates. For understanding the structural transition of these films as a function of temperature in real space and at real time, we developed a variable-temperature high-speed scanning tunneling microscope (STM).

The experimental setup consists of a two-chamber ultra-high vaccum (UHV) system including a preparation and a main chamber. The preparation chamber is equipped with standard preparation tools for sample cleaning and film growth. The main chamber hosts the STM that is located within a continuous flow cryostat for counter-cooling during high-temperature measurements. The microscope body is compact, rigid, and highly symmetric to ensure vibrational stability and low thermal drift. We designed a scanner made of two independent tube piezos for slow and fast scanning, respectively. Here we have decided to implement non-conventional spiral geometries for high-speed scanning. A Versa Module Eurocard bus system enables the fast scan control and is implemented in the EPICS software framework.

With sprial scans, we atomically resolved diffusion processes within an O(2x2) coverage on Ru(0001) and achieved a time resolution of 25 milliseconds per frame.