Source of the Ferroelectricity in MnCuSiTe₃: A Density Functional Theory Study

Multiferroic materials host both ferroelectricity and magnetism. The newly discovered compound MnCuSiTe₃ [1] displays magnetic transitions as well as ferroelectric response. Here, we investigate the source of its ferroelectricity through density functional theory calculations. The structure has a layer of Cu atoms that occupy different tetrahedral sites, each of which is coordinated above and below by Te. The apices of these tetrahedra could point either up or down depending on the lateral location of the Cu atoms. Although the ground state structure is centrosymmetric, ferroelectricity could be induced through the breaking of symmetry by means of changing the Cu positions within the copper layer, in an energy profile which has many local minima.

[1] C. De et al., Discovery of a new polar magnetic semiconductor MnCuSiTe₃ with spin-induced electric polarization (APS March Meeting 2023).