Detection of a Fermi level crossing in three-domain Si(111)-In(4x1)

Using photoemission and inverse photoemission, it has recently been demonstrated that single domain Si(111)-In(4 X 1) overlayers possess a clear Fermi level crossing at approximate to 0.6<(Gamma X)over bar However, a previous inverse photoemission study, that was performed on a three domain sample, concluded that the overlayer was semiconducting. In an attempt to reconcile the results of the two inverse photoemission studies we proposed, in an earlier paper, that the first study did not probe the region of reciprocal space where the Fermi level crossing is now known to occur. In this paper we demonstrate that this suggestion is correct. Using a three domain Sill 1 1)-In(4 x 1) overlayer, we mapped along the <(Gamma K)over bar> azimuth of the 1 x I zone, which is coincident with the <(Gamma X)over bar> azimuth of the 4 X 1 zone, with inverse photoemission, and found a Fermi level crossing at approximate to 0.6<(Gamma X)over bar>. We have now detected Fermi level crossings in both single and three domain 4X1 overlayers. [S0163-1829(99)10415-6].