No abstract

There is increasing experimental evidence for the existence of liquidlike layers on crystal surfaces and in grain boundaries, although the issue remains controversial. Recent simulations have provided definitive information on the equilibrium and dynamic properties of interfaces and clarify the conditions under which interface melting is to be expected.

We have obtained experimental confirmation of the prediction that explosive crystallization of amorphous germanium proceeds via an intermediate melting step.

We performed a theoretical investigation on the properties of iron–acceptor impurity pairs (Fe–A, with A=B, Al, Ga, and In) in silicon. The calculations were performed within the framework of an ionic model, including elastic and electrostatic interactions. In contrast to the conventional point charge ionic model, our model includes a correction to the electrostatic interaction that takes into account the valence electronic cloud polarization, which adds a short range, attractive interaction to Fe–A pair bonding, and includes the silicon lattice relaxation due to the atomic size difference between the acceptor and the lattice atoms. Our results are in good agreement with the experimental trends among the Fe–A pairs, describing the increase in the pair donor energy level with increasing A principal quantum number and decreasing pair separation distance, and the pair configurational symmetries.

We examine the behaviour of the (310) symmetric tilt boundary with applied shear stress in a face-centred cubic Lennard-Jones crystal. Our purpose is to observe the mechanical properties of grain boundaries resulting from interface melting. The grain boundary is seen to exhibit significant self-diffusion at temperatures above 80% of the bulk melting point . Excess thermodynamic properties and the density of the system change dramatically in this region. However, the system is able to resist shear up to the higher temperature of . Plots of particle trajectories in the interface and estimates of the number of melted layers provide insight into an understanding of this behaviour.