Consider a continuous structural phase transition whose only effect in Fourier space is a slight distortion of the lattice of wave vectors that lowers its rank, possibly with a reduction of its point group. Suppose we know the space group describing the crystal in its high-rank phase. What are the possible space groups describing the crystal in its low-rank phase? We illustrate here how this question is answered in the language of Fourier space crystallography.*
展开▼
