Some implementations of quantum gates (in the hopes of building a quantum computer one day) use crystals to isolate the qubits (to prevent decoherence). Why is a crystal so much better than an amorphous solid? My reasoning is that crystals tend to pack atoms more tightly than other substances, which means that lattice vibrations are less of an issue (vibrational excitations get "frozen out"). On the other hand, atoms near defects or atoms in a non-crystal are more loosely bound. Is this correct?
Crystals also contain an ordered arrangement of atoms. Does this perfect ordering help with isolation as well?