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Sublattice Identification in Scanning Force Microscopy on Alkali Halide Surfaces

“…Encouraging agreement between calculations and experiments has been obtained [3,6,7]. In contrast to surfaces of covalent materials such as Si(lll) 7 X 7 on which adatoms with dangling bonds are imaged, on ionic compounds one type of surface ion is imaged as bright, the other as dark, depending on the sign of the electrostatic potential at the tip apex [3,7]. On the CaF 2 (1 l l) surface, the sign of the potential could be identified by analyzing the asymmetry of the observed contrast [7].…”

“…In particular, alkali halide (001) and alkali earth halide (111) surfaces have been extensively studied because these insulator surfaces are easily accessible to both calculations and experiment. From a theoretical point of view, atomistic simulations based on semiempirical potentials taking the polarization and relaxation of the ions into account have succeeded in giving a detailed understanding of the interaction of these surfaces with plausible models of the probing tip [3]. From an experimental point of view, these surfaces are easy to prepare, and atomic resolution is readily achieved [4][5][6][7].…”

“…From an experimental point of view, these surfaces are easy to prepare, and atomic resolution is readily achieved [4][5][6][7]. Encouraging agreement between calculations and experiments has been obtained [3,6,7]. In contrast to surfaces of covalent materials such as Si(lll) 7 X 7 on which adatoms with dangling bonds are imaged, on ionic compounds one type of surface ion is imaged as bright, the other as dark, depending on the sign of the electrostatic potential at the tip apex [3,7].…”