An angle-resolved photoelectron spectroscopy study of the electronic structures of Si(001)2 x 2-Al and -In surfaces

摘要

Angle-resolved photoelectron spectroscopy (ARPES) using synchrotron radiation was employed to study the electronic structure of single-domain Si(001)2 x 2-Al and -In surfaces. Five different dispersing surface state bands, denoted as S_1, S_2, S_2', S_3 and S_3', are identified within bulk band gap with similar dispersions for both surfaces. From their dispersions and symmetry properties, the lowest-E_B state S_1 is assigned as the surface state due to the dimer bond within the Al (In) dimer and S_2, S_2', S_3 and S_3' due to the back bonds between Al (In) and top-most Si atoms. This result also gives a corroborating evidence for the parallel dimer model of the surface structure.