A wide-terrace single-domain Si(001)c(4×2) surface has been obtained by cooling a wide-terrace single-domain Si(001)2×1 surface to 200–80 K. Angle-resolved ultraviolet photoelectron spectra have been measured for the Si(001)c(4×2) surface at 200–100 K and compared with those for the Si(001)2×1 surface. The electronic structure of the Si(001)c(4×2) surface appears to be explained as that expected for ‘‘antiferromagnetic’’ order of asymmetric dimers of surface Si. The electronic structure of the Si(001)2×1 surface appears to be reminiscent of the c(4×2) surface.

• Received 1 June 1990

DOI:https://doi.org/10.1103/PhysRevLett.65.2704