Scanning tunneling and atomic force microscopy study of the misfit layer compounds (LaS)1.14(NbS2)n (n=1, 2) and [(Pb,Sb)S)]1.14NbS2

Abstract The misfit layer compounds (LaS) 1.14 (NbS 2 ) n ( n =1, 2) and [(Pb,Sb)S] 1.14 NbS 2 were examined by scanning tunneling microscopy (STM) and atomic force microscopy (AFM). In these compounds the NaCl-type double MS (M=La, Pb, Sb) layers (Q layers) alternate with the NbS 2 layers (H layers) made up of NbS 6 trigonal prisms. It was possible to record AFM and STM images for only the H layers for (LaS) 1.14 (NbS 2 ) n , but for both the H- and Q-layers for [(Pb,Sb)S] 1.14 NbS 2 . Partial and total electron density plots of the H and Q layers were calculated to interpret the observed STM and AFM images. The bright spots in the STM and AFM images of the H layer correspond to S atoms, and those of the Q layer to Pb and Sb atoms. The STM images for the Q layers of [(Pb,Sb)S] 1.14 NbS 2 suggest that a short-range ordering of the Pb and Sb atoms occurs in the (Pb,Sb)S sheets of the Q layer.