SPring-8, the large synchrotron radiation facility

Date : 13:30-15:00 February (TUE.), 2010

Place : Kamitsubo Hall

Speaker : Han Woong Yeom

Language : English

Affiliate : Center for Atomic Wires and Layers, Yonsei University, Seoul, Korea

Title : Bring nanowires down to the real bottom: atomic wires on silicon surfaces

Abstract :
  During last ten years, we have investigated metallic atomic wire arrays of In, Au, Gd, and Pb self-assembled on silicon surfaces. These wires have truly atomic dimension in width and thus are the thinnest wires one can get.
The motivations have been twofold; they might be (i) exploited in future
nano- or molecular-scale device architectures and (ii) useful as a new class of model systems for physics studies on low dimensional electrons. In particular, these systems feature well-defined multiple 1D electron bands, which drive Peierls-type metal-insulator transitions through strong electron-lattice interactions [1].
  In the first half of this talk, I will review the present understanding of these atomic wires focusing on the metal-insulator transitions. In the second part of the talk, I will introduce a few recent systems and issues such as Pb/Si(557) [2] and Au/Si(110), which are stable at low temperature against the Peierls instability. In these systems, interesting electron-electron interactions were observed, which lead to giant kink in the electron dispersion and the possibility of non-Fermi liquid behaviors. A few future directions in this prospering filed of researches will be suggested, such as doping and breaking down the wires into finite length rods.

References :
[1] H. W. Yeom et al., Phys. Rev. Lett. 82 (1999) 4898; J.
R. Ahn et al., Phys. Rev. Lett.  91 (2003) 196403; J. R. Ahn et al., Phys.
Rev. Lett.  95 (2005) 196402.
[2] K. S. Kim et al., Phys. Rev. Lett. 99
(2007) 196804; Nano Lett. 9, 1916 (2009).

Organizer : Toyohiko Kinoshita
PHS:3129
E-mail : toyohiko@spring8.or.jp