Electron waves in the π* surface band of the Si(001) surface

The unoccupied pi* surface band of the Si(001)-c(4 X 2) surface has been determined from standing-wave patterns using low-temperature scanning tunneling microscopy. A straight chain of Al ad-dimers, formed by deposition at room temperature, works as a one-dimensional (1D) barrier that scatters the surface-state electrons. The standing waves have been 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 sample voltages gives the dispersion relation of the pi* surface band. The height and width of the potential barrier have been estimated according to the 1D Schrodinger equation. [S0031-9007(98)07398-0].