Dresden 2009 – scientific programme

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O: Fachverband Oberflächenphysik

O 5: Nanostructures at surfaces: Wires, tubes

O 5.7: Talk

Monday, March 23, 2009, 12:45–13:00, SCH A215

Periodic LDOS modulations in self-organized bi-atomic chains — •Matthias Menzel, Kirsten von Bergmann, André Kubetzka, and Roland Wiesendanger — Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg

The (5×1)-reconstructed Ir(001) surface is an ideal template for the self-organized formation of one-dimensional nanostructures [1]. In this reconstruction, which exists in two rotational domains, the topmost layer forms trenches along the <110>-directions of the surface. We used this property of the surface to grow bi-atomic Fe chains at room temperature which we investigated by means of low temperature scanning tunneling microscopy (STM) and spectroscopy (STS).

In maps of the differential conductance (dI/dU), which is proportional to the local density of states (LDOS), the Fe chains exhibit various different periodic modulations of the LDOS along the chain axis. Those oscillations are commensurate with respect to the atomic distance in the Fe chains and we observe modulations of two, three and four times the atomic distance. The modulations are found to be non-dispersive in energy and they do not depend on the chain length.

[1] L. Hammer et al., Phys. Rev. B, 67, 125422 (2003)