A high resolution synchrotron x-ray study of the weakly-incommensurate phase of high stage bromine-intercalated graphite

We report the results of a high resolution synchrotron x-ray scattering study of the weakly incommensurate stripe domain phase of high stage bromine-intercalated graphite. The translational order in this system is two-dimensional in nature.) We demonstrate power-law behaviour at five harmonics (G) of the mass density wave, and confirm the scaling of the structure factor with G2. Our results are consistent with recent theories of the two dimensional uniaxial commensurate-incommensurate transition, which are based on an entropically wandering domain wall picture of the incommensurate phase. We demonstrate that, in this system, the domain walls have a width much less than their separation so that significant molecular displacements from the commensurate sites occur within a unit cell. Close to the transition, we observe hysteresis. © 1985 Springer-Verlag.