Edge channels of broken-symmetry quantum Hall states in graphene visualized by atomic force microscopy
Sungmin Kim, Johannes Schwenk, Daniel Walkup, Yihang Zeng, Fereshte Ghahari, Son T. Le, Marlou R. Slot, Julian Berwanger, Steven R. Blankenship, Kenji Watanabe, Takashi Taniguchi, Franz J. Giessibl, Nikolai B. Zhitenev, Cory R. Dean & Joseph A. Stroscio
Achieving μeV tunneling resolution in an in-operando scanning tunneling microscopy, atomic force microscopy, and magnetotransport system for quantum materials research
Johannes Schwenk, Sungmin Kim, Julian Berwanger, Fereshte Ghahari, Daniel Walkup, Marlou R. Slot, Son T. Le, William G. Cullen, Steven R. Blankenship, Sasa Vranjkovic, Hans J. Hug, Young Kuk, Franz J. Giessibl, and Joseph A. Stroscio
Preisträger Professor Baratoff (2. von links) mit einem aus Aluminium gefertigten Modell einer Siliziumoberfläche, welches auf vierzigmillionenfach vergrößerten experimentellen Kraftmikroskopiedaten beruht. Lokale Organisatoren Prof. Dr. F.J. Gießibl (links), Prof. Dr. J. Repp (2. von rechts), PD Dr. J. Weymouth (rechts)
Subatomare Auflösung auf Adatomen und kraftfeldabhängige laterale Manipulation mit einem eigenentwickelten Tieftemperatur-Rasterkraftmikroskop
Gerhard Ertl Award
Dr. Jay Weymouth won the Gerhard Ertl Young Investigator Award in 2015. This award is given by the Surface Science division of the German Physicist's Society (DPG) to outstanding young scientists. It is named after Prof. Gerhard Ertl (of the Fritz-Haber Institute in Berlin), who won the Nobel Prize in Chemistry in 2007.
Subatomic resolution force microscopy reveals internal structure and adsorption sites of small iron clusters
Matthias Emmrich, Ferdinand Huber, Florian Pielmeier, Joachim Welker, Thomas Hofmann, Maximilian Schneiderbauer, Daniel Meuer, Svitlana Polesya, Sergiy Mankovsky, Diemo Ködderitzsch, Hubert Ebert, Franz J. Giessibl
CO Tip Functionalization Inverts Atomic Force Microscopy Contrast via Short-Range Electrostatic Forces
Maximilian Schneiderbauer, Matthias Emmrich, Alfred J. Weymouth, and Franz J. Giessibl
What does a balloon sticking to a wall have in common with an atomic-scale insulator?
When we consider the interaction between atoms, we often think about the forming and breaking of chemical bonds that is best described with quantum mechanics. But electrostatic forces, like the ones responsible for sticking a balloon on a wall after you rub on your head, also play a role at the atomic scale. Salt, made up of sodium and chloride, is a great example of the importance of these forces. The sodium and chloride atoms have different charges that keep the salt crystal together. Nanotechnology is making use of these ionic materials at the atomic scale as an insulating layer – like the plastic coating of a wire. We used an atomic force microscope to investigate one of these materials – Copper with Nitrogen in it – at the atomic scale to see what role electrostatics plays. By picking up or putting down a molecule on the tip, we can change the charge at the end of the tip. We then simulated these two cases – with and without a molecule – using just the electrostatic interaction. The great agreement between our model and our data tell us how important these interactions are even at the scale of two atoms.
Quantifying molecular stiffness and interaction with lateral force microscopy
Alfred J. Weymouth, Thomas Hofmann, Franz J. Giessibl
One of the most impressive atomic force microscopy (AFM) images was taken by Leo Gross and coworkers at IBM of a molecule showing every carbon-carbon bond within it [Gross et al, Science 325, 1110]. A key step was to functionalize the tip with a CO molecule, making the apex of the AFM tip small and chemically inert [Bartels et al, Appl. Phys. Lett., 71, 213]. However, this comes with a complication: The CO isn’t stiff but rather pivots when a horizontal force is applied. Moreover, standard experimental and theoretical approaches have not been able to characterize this torsional spring. We modified our AFM to be sensitive to lateral forces (LFM). As we measure forces along the surface, we are highly sensitive to short-range interactions. We combined both LFM and AFM data of a CO terminated tip probing a CO surface molecule, to determine the parameters of a simple model: two torsional springs interacting via a Morse potential.