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تسجيل مستخدم جديدSpin- and angle-resolved photoemission studies of the electronic structure of Si(110)16x2 surfaces
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The electronic structure of Si(110)16 x 2 double-domain, single-domain and 1 x 1 surfaces have been investigated using spin- and angle-resolved photoemission at sample temperatures of 77 K and 300 K. Angle-resolved photoemission was conducted using horizontally- and vertically-polarised 60 eV and 80 eV photons. Band-dispersion maps revealed four surface states ($S_1$ to $S_4$) which were assigned to silicon dangling bonds on the basis of measured binding energies and photoemission intensity changes between horizontal and vertical light polarisations. Three surface states ($S_1$, $S_2$ and $S_4$), observed in the Si(110)16 x 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, $S_3$, was observed in both the Si(110)16 x 2 and 1 x 1 band maps and consequently attributed to the pervasive Si zigzag chains that are components of both the Si(110)16 x 2 and 1 x 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 x 2 surface. Whilst room temperature measurements of $P_y$ and $P_z$ were statistically compatible with zero, $P_x$ measurements of the enantiomorphic A-type and B-type Si(110)16 x 2 surfaces gave small average polarisations of around 1.5% that were opposite in sign. Further measurements at 77 K on A-type Si(110)16 x 2 surface gave a smaller value of +0.3%. An upper limit of $sim1%$ may thus be taken for the longitudinal polarisation.
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