Interaction of atomic hydrogen with the $β-SiC(100)$ $3×2$ surface and subsurface

We investigate clean and atomic hydrogen exposed $β-SiC(100)$ $3×2$ surfaces by synchrotron radiation-based Si $2p$ core-level photoemission spectroscopy. The clean $3×2$ surface reconstruction exhibits three surface and subsurface components. Upon hydrogen exposures, those surface and subsurface components are shifted to lower binding energies by large values, indicating significant charge transfer to the surface and subsurface regions, in excellent agreement with the recently discovered H-induced $β-SiC(100)$ $3×2$ surface metallization. In addition, the interaction of hydrogen results in a large reactive component at Si $2p$ supporting an asymmetric charge transfer in the third plane below the surface, in agreement with previous experimental investigations. However, the results are inconsistent with recent ab initio theoretical “frozen” calculations predicting H atom to be in a bridge-bond position.