Contributions of Scanning Tunneling Microscopy for Probing and Manipulating Electronic Properties in Low Dimensions

Abstract

Scanning tunneling microscopy (STM) is well known for its atomic resolution capability in direct space for surfaces of conducting materials. However, at first place, STM is a spectroscopic technique because the obtained images are usually bias-dependent, particularly for semiconductors. The investigation of this bias-dependence provides a key for probing electronic properties on a local scale down to atomic dimensions. Recently, it has been shown that STM can even be made sensitive to the difference in the spin configuration between neighbouring lattice sites by using ferromagnetic probe tips. With this spin-sensitive STM, a 2D Wigner glass state at the (001) surface of magnetite has directly been observed in real space at room temperature.

The finely focused, low energetic electron beam in STM can also be used for the fabrication of nanometer scale structures as well as for the modification of the local electronic structure, ultimately at the atomic level. The modified structures can subsequently be probed by STM itself.