A short-range model for the W(001) reconstruction phase transition was presented and its properties were analyzed by means of a Monte Carlo calculation. The latter determines ordering properties as well as properties that reveal the local character of the atomic displacements, including the integer-order diffraction beams and distributions of displacements. New measurements of the behaviour of the integer beams through the transition were also presented and interpreted in terms of the simulation results. The question of the character of the transition, displacive or order-disorder, was considered from a perspective in which those 2 possibilities were limiting cases. Variation along this spectrum was determined by important physical characteristics of the electronic driving force.

Nature of the Surface-Reconstruction Phase Transition and the High-Temperature Phase of Clean W(001). L.D.Roelofs, J.F.Wendelken: Physical Review B, 1986, 34, 3319-36