ISAS-Colloquium: 'Epitaxial silicene: from monolayer to multilayer and back'

ISAS-Colloquium: “Epitaxial silicene: from monolayer to multilayer and back”

Montag, 24. Februar 2020 // 14.00

Leibniz-Institut für Analytische Wissenschaften – ISAS – e.V.

Schwarzschildstraße 8, 12489 Berlin
Lecture Hall ISAS-Berlin (Room 218)

Logo: isas

Epitaxial silicene: from monolayer to multilayer and back

Dmytro Solonenko, Dr. rer. nat, TU Chemnitz

The research of elemental two-dimensional (2D) materials has been afresh blooming since the advent of epitaxial silicene [1], bestowing new possibilities of growing one-atom-thin structures at the matching, predominantly, metallic surfaces. Despite the fact that epitaxial silicene is by far the most studied member of the family, its properties, perturbed by the presence of the supporting substrate, might still be disputed when compared to the prototypical 2D material such as graphene. The absence of other suitable surfaces but Ag(111) for the silicene growth as well as its metastable nature impedes the investigation of this Si allotrope beyond the ultra-high vacuum environment and various growth conditions. Nevertheless, epitaxial silicene on Ag(111) represents a conceptual elemental 2D material, studying which allows us to improve our understanding of the ad-layer-substrate interrelations.
Apart from the conventional surface-sensitive characterization techniques, our method of choice is Raman spectroscopy, which has been proven to profitably serve for the research of 2D materials being both sensitive to the structural and electronic properties as well as their combination [2]. In this talk we will discuss the origins of the vibrational signature of silicene, the relation to its intricate electronic structure and modifications due to the substrate effects. Owing to the combination of the growth and in situ characterization of Si layers, further tailoring of silicene can be investigated in an undisturbed fashion. Among such challenges, one finds an extreme chemical sensitivity of silicene, which could be overcome via capping with, for instance, another Si layer. Thus, the super-monolayer Si deposition on Ag(111) has been examined also testing an opportunity of the existence of so-called multilayer silicene. The results show an intricate multi-phase formation based confronting diffusion mechanisms echoing recent STM studies of the system [3].

  1. P. Vogt, P. De Padova, C. Quaresima, J. Avila, E. Frantzeskakis, M. C. Asensio, A. Resta, B. Ealet, and G. Le Lay, Phys. Rev. Lett. 108, 155501 (2012).
  2. A. C. Ferrari and D. M. Basko, Nat Nano 8, 235 (2013).
  3. A. Curcella, R. Bernard, Y. Borensztein, M. Lazzeri, and G. Prévot, Nanoscale 10, 2291 (2018).

As always, all interested colleagues are cordially invited to take part in the seminar.

Lively participation is welcome.