Berlin 2018 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 58: Liquid and Amorphous Metals

MM 58.4: Vortrag

Donnerstag, 15. März 2018, 12:30–12:45, TC 010

Local atomic order of a metallic glass made visible by scanning tunneling microscopy — •Yuansu Luo and Konrad Samwer — I. Physikalisches Institut, Georg-August-Universität, D-37077 Göttingen, Germany

STM investigations on quasi low-dimensional ultrathin films Zr65Cu27.5Al7.5 were carried out to explore atomic level structure of a locally ordered system. The highly oriented pyrolytic graphite (HOPG) was chosen as substrate. It creates imaging contrasts between long-range and short-range orders, so that the structural heterogeneousness arising from competition between the glass former and the epitaxy can be ascertained. For this purpose, the film is ultrathin in an order of magnitude corresponding to the scale of short range order (SRO). A chemical order predicted for this system was observed in atomic ordered regimes, accompanied with a charge density wave. This implies a chemical short range order (CSRO) in atomic disordered regimes, where polyhedral clusters are dominant with Cu(Al) in the center. An attempt was made for structural modeling based on high resolution STM images, giving icosahedral orders on surface and different Voronoi clusters in 3-D space.