
Figure 6
Scheme illustrating the different sequence of L and L' along the a axis as a function of the modulation vector q = (a')* and t_{0}. The sequence can be deduced from the intersections of a black solid line with black (L') and grey (L) (orange in the electronic version of the journal) domains. The L domain is defined by the central point x_{4} = 0 and width = 0.5. L and L' domains are related by the unitcell centring X = 00. The coefficient in the q vector expression is equal to the tangent of the angle between the black solid line and the x_{1} axis. 