Kota Tomatsu

An Atomic Seesaw Switch Formed by Tilted Asymmetric Sn-Ge Dimers on a Ge (001) Surface

When tin (Sn) atoms are deposited on a clean germanium (Ge) (001) surface at room temperature, buckled dimers originating from the Sn atoms are formed at the Ge-dimer position. We identified the dimer as a heterogeneous Sn-Ge dimer by reversing its buckling orientation with a scanning tunneling microscope (STM) at 80 kelvin. An atomic seesaw switch was formed for one-dimensional electronic conduction in the Ge dimer–row direction by using the STM to reversibly flip the buckling orientation of the Sn-Ge dimer and to set up standing-wave states.

Multiple Electronic Excitation Using Scanning Tunneling Microscopy on Ge(001)

On the Ge(001) surface, it has previously been shown that a single-electron excitation process induces a local and reversible superstructure transformation between c (4×2) and p (2×2) by scanning tunneling microscopy. A structure transformation in the direction opposite to that of the previous result is demonstrated by increasing the tunneling current in the electron injection to the surface. In addition, the increased tunneling current shortens the range of hot electron propagation in the surface state. The observed results are attributed to the local increase in surface lattice temperature by a multiple electronic excitation process.