Angle-resolved photoemission measurements using synchrotron radiation were performed for the As-stable GaAs(001)-2 x 4 reconstruction, which was grown in situ by molecular beam epitaxy. Measurements made at high symmetry points and along symmetry lines of the surface Brillouin zones show weakly dispersing dangling bond-like surface states in the energy range between -1.6eV and the top of the valence band and a nearly dispersionless state near -3eV.

Surface Band Structure of MBE-Grown GaAs(001)-2 x 4. P.K.Larsen, J.D.van der Veen: Journal of Physics C, 1982, 15[13], L431-5