Structure and stability of the Si(001)c(4×4)-Sb surface

Abstract

Results of low-energy electron diffraction, Auger electron diffraction, low-energy ion scattering, and ab initio pseudopotential studies of submonolayer coverages of Sb on the Si͑001͒ surface indicate the existence of an ordered c(4ϫ4)-Sb reconstruction between 0.2 and 0.3 ML. Analysis of the ion-scattering data from this surface suggests an overlaid above-row structure in which Sb dimers are situated directly above Si dimer rows. Ab initio pseudopotential calculations support this conclusion and confirm that such a uniform distribution of Sb ad-dimers only becomes stable for a very narrow coverage range around 0.25 ML.

Growth process and structure of Fe/Si(1 1 1) ultrathin film: Transition from single-domain Fe(1 1 1)/Si(1 1 1) to β-FeSi2

“…CAICISS has proven to be useful in exploring surfaces and subsurface structures [14][15][16][17][18][19][20][21]. It has been revealed that Fe(1 1 1) thin films with a bcc-type structure can be epitaxially grown on a Si(1 1 1) crystal even at room temperature (RT) and form a single-domain structure.…”

Progressive changes in atomic structure and gap states on Si(001) by Bi adsorption

“…A previous study considered three plausible geometries for the Sb dimers for the 1/4 ML covered Sb/Si(0 0 1) system within an ordered c(4 · 4) reconstruction [17]. Within this surface reconstruction, three plausible overlayer dimer geometries were considered, and it was concluded that the minimum energy configuration corresponds to an overlaid above-row structure.…”

A phase diagram of the Sb/Si(001) interfacial system

“…However, in an earlier scanning tunneling microscopy and surface extended X-ray absorption fine structure study [6] it is shown that Sb dimers occupy modified bridge sites on the Si(0 0 1) surface perpendicular to the clean Si dimers for an Sb coverage of 1.0 ML. A 0.25 ML c(4 · 4) surface phase, in an 'overlaid above-row structure' formed by Sb dimers adsorbed directly above the underlying Si dimer rows, has also been recently observed [7][8][9][10] for this Sb/Si(0 0 1)-(2 · 1) system.…”

“…1d. Recent ab initio pseudopotential density functional calculations [8,9] for this c(4 · 4) phase have inferred an overlaid above row structure as the energetically most favorable configuration. In this arrangement three out of every four dimers in the 1.0 ML covered Sb adlayer are removed, leaving an array of Sb dimers bonded above the partially reformed Si dimer rows in a c(4 · 4) structure [8,18] in the 0.2-0.3 ML Sb coverage range.…”

“…Recent ab initio pseudopotential density functional calculations [8,9] for this c(4 · 4) phase have inferred an overlaid above row structure as the energetically most favorable configuration. In this arrangement three out of every four dimers in the 1.0 ML covered Sb adlayer are removed, leaving an array of Sb dimers bonded above the partially reformed Si dimer rows in a c(4 · 4) structure [8,18] in the 0.2-0.3 ML Sb coverage range. This 0.25 ML c(4 · 4) surface phase has been observed at about 770°C by Wasserfall and Ranke [7] and at about 800°C by Mitsui et al [10], but Dixon et al [8] report its observation at a lower temperature of about 600°C while attributing it to the difference in the methods of formation.…”