Surface states resonance on In-terminated InAs(0 0 1)4 x 2-c(8 x 2) clean surface

We have performed angle-resolved photoemission spectroscopy on InAs(0 0 1)4x2-c(8x2) clean surfaces in order to investigate two new electronic surface states related to the In-terminated InAs(0 0 1)4x2-c(8x2) clean surface. The experiments were carried out at normal emission as a function of photon energy using s- and p-polarized light. The surface states are strongly resonant at photon energies of 31 and 61 eV, respectively. These energies correspond also to transitions from bulk electronic states localized at high symmetry points X6, X7 and Γ7, Γ6 of the calculated InAs band structure. The intensities of the two surface states decrease when passing from s- to p-polarization of the radiation: such behaviour directly establishes the orientation of the surface state bonds