Surface states of the3C−SiC(001)−c(4×2)surface studied using angle-resolved photoemission

Abstract

We provide a detailed experimental investigation of the electronic band structure of the $3\mathrm{C}\ensuremath{-}\mathrm{SiC}(001)\ensuremath{-}c(4\ifmmode\times\else\texttimes\fi{}2)$ surface using angle-resolved photoemission and synchrotron radiation. A prominent surface state was identified at $\ensuremath{-}1.5 \mathrm{eV}$ and referred to the Fermi level, showing a downwards dispersion by about 0.2 eV. Two other surface states were found at the energies $\ensuremath{-}0.95 \mathrm{eV}$ and $\ensuremath{-}2.5 \mathrm{eV}.$ The electronic structure is semiconducting and very similar to the one for the $2\ifmmode\times\else\texttimes\fi{}1$ reconstruction, proving the close relationship between the $c(4\ifmmode\times\else\texttimes\fi{}2)$ and the $2\ifmmode\times\else\texttimes\fi{}1$ structures. Comparison to theoretical band structure calculations gives no satisfactory agreeement, leaving the question about the structure of the $c(4\ifmmode\times\else\texttimes\fi{}2)$ and the $2\ifmmode\times\else\texttimes\fi{}1$ reconstructions still open.