Melting point oscillation of a solid over the whole range of sizes

摘要

It is intriguing that a solid containing similar to 10(1) atoms of Ga or IV-A elements (C, Si, Ge, Sn, and Pb) melts at temperatures that are higher than the melting point of the corresponding bulk solid (T-m,T-b) though the T-m of a solid in the 10(0-2) nm size range drops universally with the sample size. Consistent insight into the phenomenon of Tm oscillation (suppression followed by elevation as the solid size is reduced from bulk to subnanometre size) over the whole range of sizes remains a scientific challenge. Here we show that the T-m oscillation arises from the joint effect of bond order loss and its consequence on bond strength gain of small clusters in particular for Ga and atoms of the IV-A elements.