State selective electron transport through electronic surface states of 6H-SiC(0001)-3 x 3

We investigate charge transport through electronic surface states of the 6H-SiC(0001)-3 x 3 surface. Three intrinsic surface states are located within the wide bulk band gap, in which two (S-1 and U-1) arise from strongly correlated electronic states and the third (S-2) has negligible electron correlation effects. Combined conductance and luminescence experiments with the scanning tunneling microscope show that the Mott-Hubbard surface states (S-1 and U-1) have a high resistance (1.0 G Omega), while the noncorrelated state (S-2) has a negligible resistance. Consequently, current can be selectively transported through any of these three surface states.