Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 15: Scanning Probe Techniques: STM/AFM

O 15.13: Vortrag

Montag, 16. März 2015, 18:00–18:15, MA 043

Development of cryogen-free low temperature scanning probe microscope by using a closed cycle cryostat — •Byoung Choi, Stefan Ulrich, and Ryan Murdick — RHK Technology Inc. Troy, MI 48083, USA

Low temperature scanning tunneling microscope and atomic force microscope (LT-STM/AFM) based on a closed cycle cryostat (CCC) has been recently developed. We could realize to have the microscope thermally linked but mechanically decoupled to the cryostat by using a rubber bellows filled with Helium heat exchange gas. It enables atomically resolved topographic and spectroscopic measurements on various surfaces. At the temperature as low as 14K, the tip-sample distance fluctuation has been detected as low as 2 picometer after 8 hours of cooling. With stable conditions of both microscope and controller, we could record more than 64 by 64 scanning tunneling spectra grid for over 10 hours. The lateral drift during the measurement was as low as 1 nanometer without a counter heater or a temperature controller. We will also present the high stability and reproducibility of the CCC-LT-STM/AFM with the atom resolved imaging of Si, Pt, Au and KBr surfaces with an STM and AFM combined imaging and spectroscopic technique. These results demonstrate that the CCC-LT-STM/AFM is an instrument enabling experiments on a variety of surfaces and materials at sub-angstrom resolution without using any liquid cryogen.