title: Atom-resolved analysis of an ionic KBr(001) crystal surface covered with a thin water layer by frequency modulation atomic force microscopy.
abstract: An ionic KBr(001) crystal surface covered with a thin water layer was observed with a frequency modulation atomic force microscope (FM-AFM) with atomic resolution. By immersing only the tip apex of the AFM cantilever in the thin water layer, the Q-factor of the cantilever in probing the solid-liquid interface can be maintained as high as that of FM-AFM operation in air, leading to improvement of the minimum detection of a differential force determined by the noise. Two types of images with atom-resolved contrast were observed, possibly owing to the different types of ions (K(+) or Br(-)) adsorbed on the tip apex that incorporated into the hydration layers on the tip and on the sample surface. The force-distance characteristics at the solid-water interface were analyzed by taking spatial variation maps of the resonant frequency shift of the AFM cantilever with the high Q-factor. The oscillatory frequency shift-distance curves exhibited atomic site dependence. The roles of hydration and the ions on the tip and on the sample surface in the measurements were discussed.
authors: †Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa 920-1192, Japan.
authors: Toyoko
authors: T
authors: Arai
authors: †Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa 920-1192, Japan.
authors: Masashi
authors: M
authors: Koshioka
authors: †Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa 920-1192, Japan.
authors: Kouhei
authors: K
authors: Abe
authors: ‡School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa 923-1292, Japan.
authors: Masahiko
authors: M
authors: Tomitori
authors: §Shimadzu Corporation, Kyoto 604-8511, Japan.
authors: Ryohei
authors: R
authors: Kokawa
authors: §Shimadzu Corporation, Kyoto 604-8511, Japan.
authors: Masahiro
authors: M
authors: Ohta
authors: Hirofumi
authors: H
authors: Yamada
authors: Kei
authors: K
authors: Kobayashi
authors: Noriaki
authors: N
authors: Oyabu