Photoemission studies of alpha-Sn(100)2 x 1 surface

The electronic properties of a well ordered thick layer of alpha -Sn(100), grown on InSb(100), have been studied by corelevel- and angle-resolved phot oemission spectroscopy (ARPES). The surface was a double domain 2 x 1 showi ng a sharp LEED pattern with very low background at room temperature. ARPES spectra showed the presence of a surface state S-1 dispersing along [010] direction towards higher binding energies with an overall dispersion of 1.2 eV. Such a behaviour has been observed for a similar surface state on Si(1 00)2 x 1 and Ge(100)2 x 1 (see [Semiconductor Surfaces and Interfaces, Spri nger, Berlin, 1995] and references therein) and undoubtedly attributed to S i or Ge asymmetric dimers. This result is in good agreement with the calcul ated S-1 surface state band reported in [Phys. Rev. B 58 (1998) 13698]. The Sn 4d core levels lineshape was well fitted by four components, the bulk " B" and three chemically shifted doublets at binding energies +0.220, -0.230 . and -0.490 eV with respect to "B". Here again the energy positions and am plitudes are in good agreement with the predicted surface core-levels shift s of [Phys. Rev. B 58 (1998) 13698], taking into account final state effect s, and attributed to down dimer, second layer- and up-dimer-atoms, respecti vely. (C) 2001 Elsevier Science B.V. All rights reserved.