SPECIES OF BROKEN MACROSCOPIC
CRYSTALLOGRAPHIC SYMMETRY

The aim of this database to sort out all possible reductions of macroscopic crystallographic symmetry of crystals, and to provide information on the associated changes in the macroscopic property tensors.
Typically, such symmetry reduction is encountered in various phase transitions in crystals. In this case, species identify the essence of the group-subgroup relation between the macroscopic symmetry group of the parent phase G and the macroscopic symmetry group of an oriented domain state of the low-symmetry phase F. Subgroups of 32 crystallographic point group classes generate 212 such species G > F.
The species of interest can be found within the ORDERED LIST or using the search tool summarizing the counts of the non-zero independent components of the selected macroscopic PROPERTY TENSORS of both phases. Moreover, a graphical image is given for each species, allowing to identify the indices of such components, and relations between them in both phases at a time. The database also lists the basic information about the macroscopic DOMAIN STATES associated with a real or a virtual phase transition belonging to a given species, including the number of ferroelectric and ferroelastic domain states.