Non-magnetic twin laws

Abstract

Twin laws are groups that express the symmetry relationships between two simultaneously observed domain states (domain pair) and are used to determine physical properties that can distinguish between the observed domains. A tabulation is presented of all possible non-magnetic twin laws, that is, all possible symmetry groups and twinning groups of the domain pair. Additional information is provided related to determining twin laws. This includes the coset and double-coset decomposition of point groups, the indexing and point-group symmetry of domain states, permutations of domain states, and a classification of domain states.