Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 73: Scanning Probe Methods II
O 73.7: Vortrag
Donnerstag, 3. April 2014, 12:00–12:15, WIL A317
Atomically resolved STM imaging with a single-crystal diamond tip — Vladimir I. Grushko1, •Olaf Lübben2, Alexander N. Chaika2,3, Nikolay V. Novikov1, Evgeniy I. Mitskevich1, A. P. Chepugov1, Oleg G. Lysenko1, Barry E. Murphy2, Sergey A. Krasnikov2, and Igor V. Shvets2 — 1V. Bakul Institute for Superhard Materials, Kiev, 04074, Ukraine — 2Centre for Research on Adaptive Nanostructures and Nanodevices, School of Physics, Trinity College, Dublin 2, Ireland — 3Institute of Solid State Physics RAS, Chernogolovka, Moscow district 142432, Russia
The spatial resolution of a scanning tunneling microscope (STM) can be enhanced using light element-terminated probes with spatially localized electron orbitals at the apex atom. Conductive diamond probes can provide carbon atomic orbitals suitable for STM imaging with sub-Ångström lateral resolution and high apex stability crucial for the small tunneling gaps necessary for high-resolution experiments. Here we demonstrate that high spatial resolution can be achieved in STM experiments with single crystal diamond tips. The results of STM experiments with a heavily boron-doped, diamond probe on a graphite surface; density functional theory calculations of the tip and surface electronic structure; and first principles tunneling current calculations demonstrate that the highest spatial resolution can be achieved with diamond tips at tip-sample distances of 3-5 Å when the p orbitals of the tip provide their maximum contribution to the tunneling current. At the same time, atomic resolution is feasible even at extremely small gaps with very high noise in the tunneling current.