  A detailed numerical and experimental study of the ordering of the low
temperature tetragonal phase of CuAu is presented. The numerical simulations
are based on a coarse-grained free energy derived from electronic structure
calculations of CuAu, while the experimental results are obtained from in situ
x-ray scattering. Both theoretical and experimental work indicate a subtle
kinetic competition between the ordered tetragonal phase and the metastable
modulated phase.
