By using ab initio calculations, a study was made of modification of the electronic structure of the (00▪1) surface by various point defects. These included a surface S vacancy, and various transition-metal (Pd, Au, Fe, and V) atoms which replaced a S atom. For the S vacancy, a gap state appeared with weight mainly on the Mo and S atoms which surrounded the vacancy. Substitutional atoms with a complete d-band (Pd, Au) did not exhibit magnetic polarization, and slightly modified the density-of-states near to the Fermi energy. On the other hand, incomplete d-band atoms (Fe, V) exhibited spin polarization and significantly modified states near to the band edges. By using calculated scanning tunnelling microscopic images and STS curves, it was shown that this chemical signature could be measured and used to characterize surface defects.

Scanning Tunneling Microscopy Chemical Signature of Point Defects on the MoS2(0001) Surface. J.D.Fuhr, A.Saúl, J.O.Sofo: Physical Review Letters 92[2], 026802 (3pp)