The reconstructions of the Pb(110) surface studied by low energy electron microscopy

Several reconstructions of the Pb(110) surface and their transformations have been investigated with low energy electron microscopy and diffraction. Although the c(2 X 4) order-disorder transition of the clean surface was seen clearly to be first order, variation of the transition temperature, T-tl approximate to 420 K, by at least 25 K across the surface indicates the presence of significant heterogeneity. Locally varying stress of sufficient magnitude to effect the c(2 X 4) phase transition broadening may be ultimately responsible for driving this reconstruction and its evolution into a (2 X n) form. Potassium-induced c(5 X 2) and c(2 X 4) structures, which we attribute to substrate reconstruction, have also been discovered here. These impurity-induced structures are distinguished from the clean surface reconstruction by their periodicities and/or disordering temperatures. The occurrence of both clean surface and alkali-activated c(2 X 4) reconstructions suggests that a common origin is shared with the widely studied clean and alkali-induced (1 X 2) reconstructions of the other fee metal (110) surfaces.