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Stefan Hummel: Investigation of local deformations of 2D materials by Double-Tip AFM/STM

posted 27 Jul 2015, 00:33 by info admin
Stefan Hummel*, Kenan Elibol, Bernhard Bayer, Franz Eder, Jani Kotakoski, Jannik C. Meyer
Physics of Nanostructured Mat., University of Vienna, Vienna, Austria

Gaining control over the astonishing properties of 2D materials is one of the most important tasks towards a wide range of possible applications. By applying mechanical strain it is possible to alter the electronic structure of two-dimensional crystals, such as graphene and transition metal dichalcogenides (e.g. MoS2). Up to now, most experimental methods for the investigation of strain induced effects on 2D materials are based on either employing MEMS devices or applying uniaxial strain by using a flexible substrate. In these cases one is either limited by the size and accuracy of the MEMS device or has to account for the effect of the underlying substrate. Furthermore, these methods do not allow measuring the effects of local deformation on the properties of 2D materials. Here, we show first results of a novel measurement technique based on a Double-Tip STM/AFM microscope, where the two probes approach the sample from opposite sides. With this setup, we can explore local deformations of 2D materials caused by an approaching STM tip[1], while performing AFM measurements on the same spot. By inverting this method, i.e. pushing or pulling with AFM during STM imaging, we can explore the effect of local strain on the local electronic properties of the 2D materials.

F. Eder et al., Nano Lett., 2013, 13 (5), pp. 1934-1940

Stefan Hummel is employed as PhD-Student at the University of Vienna. He is currently working on the mechanical and electrical properties of disordered 2D materials. He received his Master degree in Technical Physics from Vienna University of Technology (2014) where he theoretically studied local and non-local correlation in strongly correlated electron systems. Additionally, he has been working as Senior Researcher at FOTEC company in Lower Austria in the field of Aerospace Engineering for 6 years, where he focused on innovative energy supply and high precision electrical space propulsion concepts for satellites. He started his PhD at University of Vienna in May 2014 under supervision of Prof. Jannik C. Meyer, where his field of expertise includes STEM, SPM and Simulation of 2D materials.