Electronic structure of Si(111)2 root 7x3-(Pb,Sn) surface

An Si(1 1 1)2root7 x 3-(Pb,Sn) surface was studied by means of scanning tunneling microscopy (STM) and angle-resolved photoelectron spectroscopy (ARPES) to identify its electronic structure. The dispersion relationships along the [10 (1) over bar] direction and [(1) over bar2 (1) over bar] direction were obtained by ARPES and two surface states of S1 and S2 were clearly observed on the 2root7 x 3-(Pb,Sn) surface. There was no surface band across the Fermi level and the dispersion of both surface states S I and S2 were rather flat. The S I band had peaks at F and K points, and the S2 band had a maximum at M point. The periodicity of S1 band did not match both 2root7 x 3 and 1 x 1 surface Brillouin zones. STM images of the 2root7 x 3-(Pb,Sn) surface showed bright spot arrays and continuous bright lines that exhibit ID charge density wave along [10 (1) over bar] direction for both empty and filled states. The 2root7 x 3-(Pb,Sn) surface intrinsically has domain boundary. The surface states S1 and S2 seem to correspond to the bright spot arrays and continuous. bright lines, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.