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arXiv · 2302.01715

Dimer Coupling Energies of the Si(001) Surface

Christian Brand·Alfred Hucht·Giriraj Jnawali·Jonas D. Fortmann·Björn Sothmann·Hamid Mehdipour·Peter Kratzer·Ralf Schützhold·Michael Horn-von Hoegen
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Abstract

The coupling energies between the buckled dimers of the Si(001) surface were determined through analysis of the anisotropic critical behavior of its order-disorder phase transition. Spot profiles in high-resolution low-energy electron diffraction as a function of temperature were analyzed within the framework of the anisotropic two-dimensional Ising model. The validity of this approach is justified by the large ratio of correlation lengths, $\xi_\parallel^+/\xi_\perp^+ = 5.2$ of the fluctuating $c(4 {\times} 2)$ domains above the critical temperature $T_\mathrm{c} = (190.6 \pm 10)$ K. We obtain effective couplings $J_\parallel = (-24.9 \pm 1.3)$ meV along the dimer rows and $J_\perp = (-0.8 \pm 0.1)$ meV across the dimer rows, i.e., antiferromagnetic-like coupling of the dimers with $c(4 {\times} 2)$ symmetry.

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Christian Brand, Alfred Hucht, Giriraj Jnawali, Jonas D. Fortmann, Björn Sothmann, Hamid Mehdipour, Peter Kratzer, Ralf Schützhold, Michael Horn-von Hoegen. 2023-02-03. Dimer Coupling Energies of the Si(001) Surface. https://doi.org/10.1103/physrevlett.130.126203

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