Semiconducting surface reconstruction of p-type Si(100) substrates at 5K

We report scanning tunneling microscopy (STM) studies of the technologically important Si(100) surface that reveal at 5 K the coexistence of stable surface domains consisting of the $p(2\ifmmode\times\else\texttimes\fi{}1)$ reconstruction along with the $c(4\ifmmode\times\else\texttimes\fi{}2)$ and $p(2\ifmmode\times\else\texttimes\fi{}2)$ reconstructions. Using highly resolved tunneling spectroscopic measurements and tight binding calculations, we prove that the $p(2\ifmmode\times\else\texttimes\fi{}1)$ reconstruction is asymmetric and determine the mechanism that enables the contrast variation observed in the formation of the bias-dependent STM images for this reconstruction.