SURFACE MELTING VERSUS SURFACE NON-MELTING - AN EQUILIBRIUM SHAPE STUDY

The melting process of micron-sized Bi and Pb crystals is studied in s itu by ultrahigh vacuum scanning electron microscopy. In contrast to P b, in which only the close-packed {111} and {100} surfaces are stable up to the melting point T(m) or close to it, all faces of Bi disappear simultaneously at T(m). The difference is discussed in terms of the e nergetics of the quasi-liquid layer.