Lattice Distortions and Ferroelectricity in Antiperovskites and Antiperovskite-like Structures

Perovskite and perovskite-like ferroelectrics have been intensively studied owing to their promising applications in modern electronic devices. However, with the same crystal structure and assumably similiar versatility, antiperovskites were rarely reported as potential ferroelectrics. In this work, we study structural instabilities of a series of tetrel antiperovskite oxides A₃TtO (A = Ca, Sr, Ba; Tt = Si, Ge, Sn, Pb), as well as corresponding inverse double perovskites A₆Tt'TtO_2. Using first principles Density Functional Theory (DFT) calculations, we show that improper ferroelectricity induced by octahdedral rotations in layered inverse double perovskites is achievable, and that the dependence of the ferroelectric polarization on the tolerance factors of the parent phases displays trends similar to those observed in regular perovskite oxide heterostructures.