Berlin 2012 – scientific programme

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O: Fachverband Oberflächenphysik

O 90: Metals and semiconductors: Epitaxy and growth

O 90.2: Talk

Friday, March 30, 2012, 10:45–11:00, A 060

Atomic structure of Fe on Ir(001) - (1x1) — •Marco Corbetta, Zhen Tian, Yiqi Q. Zhang, Alvaro Augusto Leon Vanegas, Safia Ouazi, Dirk Sander, and Jürgen Kirschner — Max Planck Institute, Halle (Saale), Germany

The correlation between structural and magnetic properties of Fe monolayers makes it a particularly interesting system to investigate the impact of lattice strain on film structure, morphology and magnetism. We study the Ir(001) - (1x1) surface by STM with a W tip obtaining atomic resolution. We then deposit 0.6 ML of Fe at 300 K and we observe a (3x3) periodicity on one layer height Fe islands at 8 K in STM constant current images. This suggests the formation of a coincidence structure where three Ir-Ir atomic distances along the [110] crystallographic direction correspond to two bcc Fe-Fe atomic distances in the same direction. The difference in length between three Ir-Ir (8.145 A) and two Fe-Fe (8.105 A) atomic distances is only +4 pm and this makes our model a reasonable proposition. After deposition of 1.2 ML of Fe we observe a (1x1) contrast by STM on the closed first Fe monolayer, in agreement with earlier studies [1]. The analysis reveals a nearest neighbour spacing of the Fe monolayer which corresponds to that of the Ir substrate. Our findings could be ascribed to a structural rearrangement within the Fe deposit with increasing Fe coverage. [1] V. Martin, W. Meyer, C. Giovanardi, L. Hammer, K. Heinz, Z. Tian, D. Sander and J. Kirschen, Phys. Rev. B 76, 205418 (2007).