It was noted that the clean (100) surface reconstructed at low temperatures to form a commensurate c(72 x 2)R45 displacement wave. Low-energy electron diffraction studies at temperatures ranging from 10 to 300K revealed a change in the harmonic content of this wave at intermediate temperatures. This corresponded to a sharpening of antiphase domain walls as the temperature was lowered. At the same time, one of two possible domain orientations occurred if steps were present. The process exhibited no hysteresis and permitted the equilibrium distribution to be observed.

R.S.Daley, T.E.Felter, M.L.Hildner, P.J.Estrup: Physical Review Letters, 1993, 70[9], 1295-8