Dresden 2014 – wissenschaftliches Programm

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SYOM: Symposium One-dimensional Metals: Reality or Fiction

SYOM 2: Posters: One-Dimensional Metals: Reality or Fiction (jointly organized by DS, HL, O, TT)

SYOM 2.18: Poster

Donnerstag, 3. April 2014, 16:00–19:00, P1

Oxygen Adsorption on the In/Si(111) Nanowire Array: Structure and influence on metal insulator transition — •Stefan Wippermann¹, Duck Mahn Oh², Han Woong Yeom², and Wolf Gero Schmidt³ — ¹Max-Planck-Institute for Iron Research, Düsseldorf — ²Pohang University of Science and Technology — ³University of Paderborn

The ordered array of In nanowires that self-assembles at the Si(111) surface is an extremely popular model system for one-dimensional (1D) electronic systems. It exhibits an intriguing metal-insulator (MI) transition, that was recently shown to occur as a first order transition starting from condensation nuclei. While the nature of these condensation nuclei remains controversial, Oxygen has recently been observed experimentally to facilitate the metal-insulator transition.

Here we present density functional theory calculations to study the influence of O adsorption on the structural properties and the MI transition of the In/Si(111)-(4x1)/(8x2) nanowire array. We find three different low energy adsorption sites. However, a single oxygen adsorbed at any of these sites does not facilitate the phase transition. Instead, two oxygen atoms acting in concert catalyze the MI transition by lowering the energy barrier for the formation of 4x2 In hexagons. These in turn act as condensation nuclei for the MI transition.

S. Wall, B. Krenzer, S. Wippermann, S. Sanna, F. Klasing, A. Hanisch-Blicharski, M. Kammler, W. G. Schmidt, M. Horn-von-Hoegen, Phys. Rev. Lett. 109, 186101 (2012)