Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 47: Poster Electron-driven Processes

O 47.4: Poster

Tuesday, March 18, 2025, 18:00–20:00, P2

Creation, Displacement, and Dynamics of Individual Phasons on Si(001) — •Gaël Reecht, Michael Horn-von Hoegen, and Manuel Gruber — Universität Duisburg-Essen, Duisburg, Germany

The Si(001) surface, characterized by buckled dimers resulting from dangling bond pairing, exhibits a variety of structural configurations. The energetically favorable c(4x2) reconstruction can be manipulated into the p(2x2) configuration, differing by a glide of adjacent rows. The interface between these two phases is known as a phason [1]. Despite its significance in structural phase transitions, the mechanisms driving phason propagation remain poorly understood.

In this study, we employ low-temperature scanning tunneling microscopy to explore the diffusion of individual phasons under tip-induced excitation. We systematically examine the effects of tunneling current, bias voltage, and electric field on the formation and displacement of these structural defects. Phason motion below the STM tip results in stochastic jumps in tunneling current, which we analyze through time-resolved measurements. These findings shed light on the displacement dynamics of phasons and enhance our understanding of the underlying processes. We gratefully acknowledge funding from the CRC1242. [1] Y. Pennec et al., Phys. Rev. Lett., 96, 026102 (2006).

Keywords: Scanning tunneling microscopy; Surface dynamics; Stochastic processes