By means of first-principles calculations we predict the stability of silicene as buckled honeycomb lattice on passivated substrates of group-IV(111)1 × 1 surfaces. The weak van-der-Waals interaction between silicene and substrates does not destroy its linear bands forming Dirac cones at the Brillouin zone corners. Only very small fundamental gaps are opened around the Fermi level.

Silicene adsorbed on a hydrogen-passivated Si(111)1 × 1 surface (H: red, Si: blue).

(© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Silicene on hydrogen‐passivated Si(111) and Ge(111) substrates

Growth and structure of Fe, Co and Ni films on hydrogen-terminated Si(111) surfaces

To optimize the structure±property relationship of layered systems exhibiting giant magnetoresistance (GMR) or tunneling magnetoresistance (TMR), there is a call for textured or epitaxial ferromagnetic layers deposited on semiconductor substrates. For high-performance GMR and TMR devices the interface properties (roughness, electronic interface states, spin polarization, phase purity, etc.) of the ferromagnetic/non-ferromagnetic metal layers (GMR) and ferromagnetic metal/insulator hybrid structures (TMR) play a crucial role. Currently, the astate-of-the-arto theoretical models for GMR and TMR systems are mainly developing calculations for epitaxial layers. Therefore the experimental investigation of epitaxial model systems becomes indispensable. In order to grow high-quality (textured or epitaxial) Co thin films on oxide-free Si substrates the possible advantages of Hpassivated Si(111) substrates have been explored. The latter can be prepared by aex situo wet-chemical processes and introduced easily into ultra high vacuum (UHV). The most reliable and reproducible results have been achieved on H-passivated Si(111) surfaces, although this crystal orientation may not yield continuous epitaxial growth of face-centered cubic (fcc) metal layers. In order to avoid silicide formation at the Co±Si interface, the influence of Ag buffer layers has been investigated. The influence of Ag deposition at elevated temperatures (ahoto Ag deposition at T = 550 C) on the formation of Si(111)-(2n+1)(2n+1) reconstructions will be discussed and compared with the results of the reconstruction formation on a H-Si(111) surface after H-desorption by thermal annealing. The influence of Ag deposited at a lower temperature (acoldo Ag deposition at T = 250 C) on the awet preparedo H-Si(111) surface has also been investigated and compared with the hot Ag deposition at 550 C on H-Si(111). In this paper, growth modes of Co and Ag on H-passivated Si(111) substrates will be presented and discussed with regard to possible applications for magnetoelectronic devices.

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J. M. Choi

Papers

The Growth of Transition Metals on H‐Passivated Si(111) Substrates