Possible appearance of superconductivity on Si(100) surface

A two-leg ladder Hubbard model with three Fermi surfaces are studied as a m odel Hamiltonian of a Si(0 0 1) surface, on which STM experiments [Phys. Re v. B 61 (2000) R5078: Surf. Sci. 452 (2000) L318] recently reported that th e p(2 x 1) symmetric dimer phase is stable at low temperatures. The fluctua tion-exchange method is adopted in order to take account of the effects of on-site Coulomb interactions. The electronic structures are discussed and a n unconventional even-parity superconductivity through large antiferromagne tic spin fluctuations is found for a wide range of doping. Other possible e lectronic states with large superconducting fluctuations are also discussed [J. Phys. Soc. Jpn. 69 (2000) 1962]. (C) 2001 Elsevier Science B.V. All ri ghts reserved.