High resolution STM imaging with oriented single crystalline tips

Precise knowledge of the atomic and electronic structure of scanning tunneling microscopy (STM) tips is crucial for a correct interpretation of atomically resolved STM data and an improvement of the spatial resolution. Here we demonstrate that tungsten probes with controllable electronic structure can be fabricated using oriented single crystalline tips. High quality of the [0 0 1]-oriented W tips sharpened in ultra high vacuum was proved by electron microscopy. Distance dependent STM studies carried out on a graphite (0 0 0 1) surface demonstrate that application of crystallographically oriented single crystalline tips allows one to control the tip electron orbitals responsible for high resolution imaging under specific tunneling conditions.

Graphical abstractDownload full-size imageHighlights► [0 0 1]-oriented single crystalline W tips have been applied for high resolution STM studies. ► Electron orbitals of the tungsten tip atom have been imaged with sub-Ångstrom lateral resolution using carbon atomic orbitals. ► The electron orbitals responsible for STM imaging can be selected by bias voltage and tip-sample distance.