Structurally-Based Prediction of Ferroelectricity in Inorganic Materials with Point Group 6mm.

Ferroelectric crystals are technologically important for their optoelectronic properties. Ferroelectricity is predictable on the basis of structural criteria, as is the temperature at which the ferroelectric phase transforms to the paraelectric phase. A systematic approach to ferroelectric prediction has been started, using the Inorganic Crystal Structure Database with its 2703 entries on polar space group materials. Two new families of compounds satisfy the structural criteria for ferroelectricity in space group P6 sub 3 cm and five new families in P6 sub 3 mc. In addition, nine other compounds in point group 6mm may ferroelectric. Three further families and four additional compounds are either ferroelectric or are not polar but instead may be centrosymmetric.