Dynamics of the Si(100) surface

Oxidation of dimers at the Si(100) surface studied by first‐principles simulation of high‐resolution EELS

“…Indeed, a proper consideration of excitonic effects improves the agreement with the data of Gavioli et al [30]. Closer inspection suggests that the low energy peak of Gavioli et al is consistent with a mixture of (predominantly) c(4 Â 2) and p(2 Â 2) reconstructions, with the latter giving rise to the observed shoulder.…”

“…From the figure it is evident that the S 0 peak and its shoulder correspond to the SDR structure observed by Chabal et al [32] between 0.6 and 0.9 eV. No clear explanation of this SDR peak has been given so far: previous explanations involved indirect transitions or instantaneous presence of symmetric p(2 Â 1) dimers (in this case, the S 0 peak moves to lower energies and would appear at $ 0:7 eV) [30]. Although a small contribution of the latter effect probably is present in the experimental S 0 [25], the main contribution is explained in terms of transitions between c(4 Â 2) or p(2 Â 2) bulk and surface states.…”

“…The curves shown are an average over spectra computed for q k aligned along [110] and ½110. Calculated spectra are compared with the experimental data of Farrell et al [29] and Gavioli et al [30], which correspond to very similar kinematic conditions (specular scattering at 608; incident energy of E i ¼ 7 or 6.8 eV). The experimental spectra are characterized by two peaks: the S 0 peak at 0.8-1.0 eV, having a shoulder around 0.7 eV, and the S 1 centered at 1.3 or 1.7 eV, depending on the experiment.…”

Theory of the temperature dependent dielectric function of semiconductors: from bulk to surfaces. Application to GaAs and Si

“…[5]. In fact, it has already been demonstrated in 1997 that the consideration of the dynamics of surface atoms is crucial to explain an appearance of the low energy peak measured by high resolution electron energy loss spectroscopy (HREELS) at Si(100) 2 Â 1 [6]. The HREELS spectra in Ref.…”

“…The HREELS spectra in Ref. [6] have been calculated within the tight binding (TB) approximation for numerous instantaneous atomic configurations, obtained from ab-initio molecular dynamics (AIMD) [7], and then averaged. It was proven that the thermally induced dimer flipping at the clean reconstructed Si(100) surface (instantaneous symmetric dimers [7]) is responsible for the effect observed.…”