AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Thursday Sessions
       Session NS-ThA

Paper NS-ThA6
Induced Growth of Calcite and Gypsum using an Atomic Force Microscope@footnote 1@

Thursday, November 3, 2005, 3:40 pm, Room 210

Session: Nano Processing
Presenter: A.L. McEvoy, Washington State University
Authors: A.L. McEvoy, Washington State University
F. Stevens, Washington State University
S.C. Langford, Washington State University
J.T. Dickinson, Washington State University
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Bond breaking at surfaces due to stimuli such as exposure to energetic radiation, mechanical stress, or chemical agents is well established. We examine the consequences of combining localized mechanical stress (due to contact with the tip of an atomic force microscope) and exposure to aqueous solutions. We show that we can induce highly localized, nanometer scale growth on single crystal surfaces of calcite (CaCO@sub 3@), an important biomineral, and gypsum (CaSO@sub 4@-2H@sub 2@O) through combined exposure to supersaturated solutions and mechanical stress. Growth occurs along step edges in single atomic layers. The growth rates depend strongly on step orientation. Tip induced deposition is shown to produce surfaces free of obvious defects, in contrast with spontaneous growth in highly supersaturated solutions (@sigma@ > 5). Experimental evidence is presented for tip-enhanced transport of ions to deposition sites. Implications concerning deposition and maintenance of atomically smooth surfaces, including mammalian joints, will be discussed. @FootnoteText@ @footnote 1@This work was supported by the National Science Foundation.