ELECTRON WAVES IN THE PI-ASTERISK SURFACE BAND OF THE SI(001) SURFACE

The unoccupied pi surface band of the Si(001)-c(4 X 2) surface has be en determined from standing-wave patterns using low-temperature scanni ng tunneling microscopy. A straight chain of Al ad-dimers, formed by d eposition at room temperature, works as a one-dimensional (1D) barrier that scatters the surface-state electrons. The standing waves have be en observed along Si dimer rows in a sample voltage range of 0.9-1.3 V at T = 63 K. The relationship between their wavelengths and the sampl e voltages gives the dispersion relation of the pi surface band. The height and width of the potential barrier have been estimated accordin g to the 1D Schrodinger equation. [S0031-9007(98)07398-0].