OCCUPIED SURFACE-STATE BANDS OF BI(1X1) OVERLAYERS ON AN INAS(110) SURFACE GROWN BY MOLECULAR-BEAM EPITAXY

The ordered p (1 X 1) monolayer phase of Bi on InAs(110) has been studied with the technique of angle-resolved ultraviolet photoemission spectroscopy. Three Bi-induced surface-state bands (S',S'', and S''') have been observed. Their respective band dispersions have been mapped along the high-symmetry lines of the surface Brillouin zone. The upper two bands, S' and S'', appear to be degenerate across most of the surface Brillouin zone except along the GAMMABAR-XBAR' symmetry line. The bandwidths of the Bi-induced states of Bi/InAs(110) are significantly narrower than that of Bi/GaAs(110) or Sb/GaAs(110). The polarization of these surface-state bands has been measured and compared to predictions of current theoretical models for Sb/GaAs(110).