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

Abstract

It is intriguing that a solid containing∼101 atoms of Ga or IV-A elements (C, Si, Ge, Sn, and Pb) melts at temperaturesthat are higher than the melting point of the corresponding bulk solid(Tm,b) thoughthe Tm of asolid in the 100–2 nm size range drops universally with the sample size. Consistent insight into the phenomenon ofTm oscillation (suppression followed by elevation as the solid size is reduced from bulk to subnanometresize) over the whole range of sizes remains a scientific challenge. Here we show that theTm oscillation arises from the joint effect of bond order loss and its consequence on bondstrength gain of small clusters in particular for Ga and atoms of the IV-A elements.