Have you got a tin or would you prefer a glass?

One result on which early high pressure crystallographers agreed is that under pressure III-V semiconductors transformed from the zincblende structure to the tin structure. Recent experimental work has shown in one system after another that this structure is not present.

In this talk I will discuss what the actual crystal structures are, explain in terms of nearly-free-electron theory (i.e. undergraduate level quantum mechanics) why the early experimenters got it wrong, and then show how the ordering of two species in tin can be mapped onto an Ising model, which then exhibits ordered, disordered and glassy phases.

Finally I will examine the transitions into and out of the glassy phase to draw some more pretentious insights into the nature of the glass and timescales of Monte Carlo dynamics.

Health warning: While every attempt has been made to prepare it carefully, this product may include equations.

References:
Preprint at https://www.ed.ac.uk/~graeme/betatinprl.ps