Decoding the surface of a complex oxide.

Atomic force microscopy reveals the elusive structure of the aluminum oxide surface.

Lateral Force Microscopy Reveals the Energy Barrier of a Molecular Switch.

Copper phthalocyanine (CuPc) is a small molecule often used in organic light emitting diodes where it is deposited on a conducting electrode. Previous scanning tunneling microscopy (STM) studies of CuPc on Cu(111) have shown that inelastic tunneling events can cause CuPc to switch between a ground state and two symmetrically equivalent metastable states in which the molecule is rotated. We investigated CuPc on Cu(111) and Ag(111) with STM and lateral force microscopy (LFM).

Quantifying molecular stiffness and interaction with lateral force microscopy.

The spatial resolution of atomic force microscopy (AFM) can be drastically increased by terminating the tip with a single carbon monoxide (CO) molecule. However, the CO molecule is not stiff, and lateral forces, such as those around the sides of molecules, distort images. This issue begs a larger question of how AFM can probe structures that are laterally weak.

The influence of chemical bonding configuration on atomic identification by force spectroscopy.

The force between two atoms depends not only on their chemical species and distance, but also on the configuration of their chemical bonds to other atoms. This strongly affects atomic force spectroscopy, in which the force between the tip of an atomic force microscope and a sample is measured as a function of distance. We show that the short-range forces between tip and sample atoms depend strongly on the configuration of the tip, to the point of preventing atom identification with a poorly defined tip.