Spin- and angle-resolved photoemission studies of the electronic structure of Si(110)“ 16 × 2 ” surfaces
Résumé
The electronic structure of Si(110)“16×2” double-domain, single-domain, and 1×1 surfaces have been
investigated using spin- and angle-resolved photoemission at sample temperatures of 77K and 300K. Angle-resolved photoemission was conducted using horizontally and vertically polarized 60 eV and 80 eV photons.
Band-dispersion maps revealed four surface states (S1 to S4) which were assigned to silicon dangling bonds on
the basis of measured binding energies and photoemission intensity changes between horizontal and vertical
light polarizations. Three surface states (S1, S2, and S4), observed in the Si(110)“16×2” reconstruction, were
assigned to Si adatoms and Si atoms present at the edges of the corrugated terrace structure. Only one of the
four surface states, S3, was observed in both the Si(110)“16×2” and 1×1 band maps and consequently attributed
to the pervasive Si zigzag chains that are components of both the Si(110)“16×2” and 1×1 surfaces. A state
in the bulk-band region was attributed to an in-plane bond. All data were consistent with the adatom-buckling
model of the Si(110)“16×2” surface. Whilst room temperature measurements of Py and Pz were statistically
compatible with zero, Px measurements of the enantiomorphic A-type and B-type Si(110)“16×2” surfaces gave
small average polarizations of around 1.5% that were opposite in sign. Further measurements at 77K on A-type
Si(110)“16×2” surfaces gave a smaller value of +0.3%. An upper limit of ∼1% may thus be taken for the
longitudinal polarization.
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