PREMELTING OF THIN WIRES

We have investigated the melting behavior of thin lead wires using molecular dynamics. We find thatin analogy with cluster meltingthe melting temperature Tm(R) of a wire with radius R is lower than that of a bulk solid Tmb by Tm(R)=Tmb-c/R. Surface melting effects, with formation of a thin skin of highly diffusive atoms at the wire surface, are observed. The diffusivity is lower over (111)-oriented faces, and higher at (110) and (100) rounded areas. The possible relevance to recent results on nonrupturing thin necks between a scanning tunnel microscope tip and a warm surface is addressed. © 1995 The American Physical Society.