Jm. Lopezsancho et al., SPIN CORRELATION-EFFECTS ON THE BONDING CHARACTER OF ALKALI SILICON INTERFACES - AN EXTENDED HUBBARD-MODEL, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 11(5), 1993, pp. 2483-2486
Recent calculations strongly suggest assuming an antiferromagnetic spi
n arrangement for the Si(100)-(2x1) reconstructed surface. The implica
tions of this assumption for the alkali-covered surface are here studi
ed by means of an extended Hubbard model. Whereas the substrate underg
oes a gradual insulator-to-conductor transition with increasing covera
ge, the adlayer suddenly metallizes above a critical coverage value. R
ecent core-level data are not incompatible, as previously believed, wi
th an ionic bond description of this interface.