Nano-scale studies of quantum phenomena by scanning probe spectroscopy

Phenomena on the nanometer scale are dominated by quantum effects. They can be visualized in a fascinating way either by the scanning tunneling micros cope (STM), which itself is based on a quantum-mechanical effect, electron tunneling, or by related scanning probe methods. These so-called near-field microscopies allow the direct observation of the wave nature of electrons in solids and the determination of their effective mass as well as their sp in state. Atomic resolution is obtained by STM on an energy scale which is a,million times smaller than that of X-rays. Therefore, quantum effects in solids, which usually occur on energy scales of several millielectronvolts, become accessible while operating at high spatial resolution down to the a tomic level. The detailed understanding of quantum phenomena at the nanomet er scale will constitute the foundations of the nanotechnology age, which w ill be dominated by the digital control of matter at the level of single at oms and molecules, single electrons, as well as single spins.