Polarization dependence of Ge(111)2×1 surface-state absorption using photothermal displacement spectroscopy: A test of surface reconstruction models
Marjorie A. Olmstead, Nabil M. Amer · Physical review. B, Condensed matter · 1984
The polarization dependence of surface-state absorption of Ge(111)2\ifmmode\times\else\texttimes\fi{}1 single-domain surfaces has been directly measured using photothermal displacement spectroscopy. The absorption at 0.5 eV is maximum for incident light polarized perpendicular to the period-doubling direction of the 2\ifmmode\times\else\texttimes\fi{}1 reconstruction. As the polarization direction is rotated, the absorption follows a ${cos}^{2}\ensuremath{\theta}$ dependence. This result supports the $\ensuremath{\pi}$-bonded chain model for the surface reconstruction, and is the same as that recently reported for the dangling-bond absorption of Si(111)2\ifmmode\times\else\texttimes\fi{}1.