Electronic structure of the single-domain Si(001)21-K surface

A single-domain Si(001)2×{}1-K surface has been made by K deposition onto a room-temperature single-domain Si(001)2×{}1 substrate. Angle-resolved ultraviolet photoelectron spectra have been measured for the single-domain Si(001)2×{}1-K surface. The work on the single-domain surface has made it possible for the first time to identify the existence of two surface-state bands and dispersions of the two bands. The resulting surface-state bands are in principle consistent with a recently proposed K double-layer model [Phys. Rev. B 37, 9097 (1988)] rather than with the more widely believed one-dimensional alkali-metal-chain model.