Spectroscopic fingerprints of a surface Mott-Hubbard insulator: the case   of SiC(0001)
  We discuss the spectroscopic fingerprints that a surface Mott-Hubbard insulator should show at the intra-atomic level. The test case considered is that of the Si-terminated SiC(0001) sqrt{3}xsqrt{3} surface, which is known experimentally to be insulating. We argue that, due to the Mott-Hubbard phenomenon, spin unpaired electrons in the Si adatom dangling bonds are expected to give rise to a Si-2p core level spectrum with a characteristic three-peaked structure, as seen experimentally. This structure results from the joint effect of intra-atomic exchange, spatial anisotropy, and spin-orbit coupling. Auger intensities are also discussed. 
G. Santoro (1), S. Scandolo (1), E. Tosatti (1 and 2) ((1) SISSA and   INFM, Via Beirut 2, Trieste, Italy, (2) ICTP, Trieste...