Fine electronic structure of the buckled dimers of Si(100) elucidated by atomically resolved scanning tunneling spectroscopy and bias-dependent imaging
Physical Review B (Condensed Matter)
We have combined spatially resolved scanning tunneling spectroscopy ͑STS͒ measurements with biasdependent scanning tunneling microscope imaging of the buckled dimers of Si͑100͒, both carried out at an unprecedented spatial resolution. By combing both aspects, in a very unambiguous way, we can elucidate the detail of the electronic structure of the Si͑100͒ surface that has not been addressed or has been misunderstood before. Our measurements clearly show that the third peak ͑located at ϳϩ1.5 V͒
... ocated at ϳϩ1.5 V͒ in the STS spectra cannot be attributed to the upper edge of the * surface band as previously believed. Analyses of our data suggest that the third peak could be attributed to the dimer bond (D 1 ,D i *) states. Theoretically predicted charge transfer between the atoms of the dimer, which is the key factor determining both the atomic and electronic structure of the dimer, was directly confirmed for the first time. Our results imply that the empty * surface state is localized closer to the Fermi level than previously understood, a point that should be treated with great care in future surface science researches.