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Limitation of metallic sharpness from local electric field

  1. Oct 30, 2007 #1
    Since there is a significantly-above atomic limit to the allowed sharpness of an (approximately zero-dimensional) needle point due to its local electric field, would there be a similar limit to the keenness of an (approximately one-dimensional) razor edge?
  2. jcsd
  3. Oct 31, 2007 #2


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    Staff: Mentor

    The limitations are related to materials and the geometry of tools used to make needles and razors.

    The sharpest point would be a single atom, and this is only achieveable with atomic force microprobes. IBM scientists have done some amazing work with AFMs.


    More generally -



    Unfortunately, I can't find a general paper or site that gives details on AFM's.
  4. Oct 31, 2007 #3

    By "sharpness" I mean in terms of slimness, as in least solid angle for a needle. The probes you mention (granting the terminal atoms) are rather blunt nonetheless. My E-M professor once mentioned that the sharpness of metallic "spline" was limited (somewhat related to the effect of a lightning rod or comb teeth on a van de Graaff generator) by spontaneous fracture of its tip. So a needle, or spline, could only be so pointed, not from atomic considerations so much, but from the concentration of electric field in its above atomic scale tine.
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