ATOMIC-STRUCTURE OF A RECONSTRUCTED SI(001)-(2X1) SURFACE

The surface structure of Si(001)-(2 x 1) was studied using coaxial imp act-collision ion-scattering spectroscopy(CAICISS). The intensity of t he backscattered particles was measured as a function of the incident angle at room temperature. By applying the symmetric and the asymmetri c dimer models to the experimetal data, we found that the structure of the Si(001) surface was mixed with symmetric and asymmetric dimers. T he fraction of asymmetric dimers in a Si(001) clean surface was found to be around 20% at room temperature.