Abstract
Surface reconstructions on the hydrogenated Si(100):H surface are observed and investigated by using a low-temperature (5 K) scanning tunneling microscope (STM). In addition to the well established and phases, linear structures extending over one to six silicon dimers along the same dimer row are observed. After a careful analysis of the corresponding STM topographies for both -type and -type doped silicon substrates, we conclude that these structures are dihydride dimers. This assignment is supported by ab initio density-functional calculations of the local density of states of dihydride structures of one or two dimers long. Furthermore, the calculation of the free-energy formation of our observed structure shows that their creation is closely linked with the hydrogenation process. These results demonstrate that the previous assignments of “split dimer” and “bow-tie” structures to dihydride dimers and dopant pairs, respectively, need to be reconsidered.
- Received 17 March 2008
DOI:https://doi.org/10.1103/PhysRevB.78.165302
©2008 American Physical Society