Identifying the electronic properties of the Ge(111)-(2$\times$1) surface by low temperature scanning tunneling microscopy

We present the results of our low temperature scanning tunneling microscopy (STM) investigation of the clean Ge(111) surface. Our experiments enable the first time STM observation of one-dimensional surface screening around surface defects. We identify the dominating role of surface states in the low temperature STM imaging as well as the important influence of non-equilibrium kinetics on the measured tunneling spectra.