OBSERVATION OF QUANTUM-SIZE EFFECTS AT ROOM-TEMPERATURE ON METAL-SURFACES WITH STM

Surface steps act as confining barriers for electrons in metal-surface states. Thus, narrow terraces and small single-atom-high metal island s act as low-dimensional, electron-confining structures. In sufficient ly small structures, quantum-size effects are observable even at room temperature. Scanning tunneling spectroscopy is used to image the prob ability amplitude distributions and discrete spectra of the confined s tates. Examination of the electronic structure of the steps provides e vidence for electron-density smoothing and the formation of step-edge states. Estimates of the electron-confining barriers are obtained.