Atomic structures of field evaporated solid surfaces

1 Atomic structures of field evaporated solid surfaces 

It is found that for metals, low temperature field evaporation almost always produces surfaces with the (1 x 1) structure, or the structure corresponding to the truncation of a solid. A few such surfaces have already been shown in Fig. 2.32. That this should be so can be easily understood. For metals, field penetration depth is usually less than 0.5 A,1 or much smaller than both the atomic size and the step height of the closely packed planes. Low temperature field evaporation proceeds from plane edges of these closely packed planes where the step height is largest and atoms are also much more exposed to the applied field. Atoms in the middle of the planes are well shielded from the applied field by the itinerant electronic charges which will form a smooth surface to lower the surface free energy, and these atoms will not be field evaporated. Therefore the surfaces produced by low temperature field evaporation should have the same structures as the bulk, or the (lxl) structures, and indeed with a few exceptions most of the surfaces produced by low temperature field evaporation exhibit the (1 x 1) structures. 

If field evaporation is done at high temperatures where jumping of an 

Cambridge Books Online Cambridge University Press, 2009 

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