Surface states and reconstruction of epitaxial √3 × √3 R30° Er silicide on Si(111)

Abstract

The surface electronic structure of epitaxial &3 X &38.30 ErSi& 7 layers on Si(111)has been studied by high-resolution angle-resolved ultraviolet photoemission spectroscopy. Typical surface states or resonances are unambiguously identified and their band dispersions mapped along the high-symmetry I M, I I(, and E M lines of the (1 X 1) surface Brillouin zone. These data are compared to the band structure of two-dimensional p (1 X 1) Er silicide extensively studied in previous works. It is found that the prominent surface bands observed in the 0 -3-eV binding-energy range can be readily derived from the p(1X 1) surface-silicide bands folded back into the reduced &3 X &3 zone. This indicates that the bulk silicide is also terminated with a buckled Si layer without vacancies, quite similar to the surface-silicide termination. In particular, specific surface bands reflect the doubly (essentially) occupied dangling bonds and the back bonds of the buckled Si top layer.

Energy surfaces of rare-earth silicide films on Si(111)

“…For the monolayer, a metallic band structure was reported with electron pockets at the M points and rather isotropic effective masses and a hole pocket at the C point [14,15]. In the multilayer silicides, similar states were found, while zone folding effects resulted in a smaller surface Brillouin zone [16]. Recently, Fermi surface maps were presented for yttrium and gadolinium silicide monolayers on Si(1 1 1), showing first indications of anisotropic effective masses at the M points [17].…”

“…[16], with the exception of the effective masses around the M and C points, which are again rather anisotropic, and the observation of the second band of the monolayer silicide (yellow lines). From the series of energy surfaces in Fig.…”

“…7c by the solid lines, while the dashed lines represent the dispersion curves additionally reported in Ref. [16]. In C À K 0 À M direction (Fig.…”

“…The electronic structure of these films has been investigated previously using angle-resolved photoelectron spectroscopy (ARPES) mainly for the case of erbium silicides [14][15][16]. For the monolayer, a metallic band structure was reported with electron pockets at the M points and rather isotropic effective masses and a hole pocket at the C point [14,15].…”

Atomic structure of thin dysprosium-silicide layers on Si(111)

“…Silicides of the trivalent rare earth metals grown as thin films on silicon surfaces are currently of high interest because of their low Schottky-barrier heights on n-type substrates [1][2][3][4][5], their epitaxial growth on Si(1 1 1) [6][7][8][9][10][11][12][13][14][15][16][17][18] and the self-organized formation of nanowires on Si(0 0 1) [19][20][21][22][23]. These silicide films can be prepared by rare-earth deposition and subsequent annealing.…”