STUDIES OF CONFINED STATES AND QUANTUM-SIZE EFFECTS WITH SCANNING-TUNNELING-MICROSCOPY

Scanning tunneling microscopy (STM) provides new ways for studying ele ctron confinement and quantum size effects and expands the range of ma terials and conditions under which such effects can be observed. Here we discuss three applications: (a) The confinement of electrons in met al surface states by surface steps or by corrals fabricated using sing le atoms, and the imaging of the probability amplitudes of the resulti ng confined states; (b) the detection of electron states involving con finement between the surface layer and sub-surface interfaces; (c) the observation of quantized conductance at room temperature using metal structures formed by the STM tip.