The general-purpose SCAN meta-GGA for ferroelectric materials*

The strongly constrained and appropriately normed (SCAN) meta-GGA was found to be accurate for geometries and energies of diversely-bonded materials. Here, we investigate its performance for the structural and electric properties of ferroelectric materials [1]. Ferroelectricity originates from the breaking of spatial inversion symmetry, and spontaneous polarization is determined by the polar structural distortion. Although DFT has been widely used for studying ferroelectric properties, an accurate prediction of the distortion is rather challenging and is limited by the adopted exchange-correlation functionals. LDA is usually more reliable than the GGAs for perovskites, but LDA usually strongly underestimate the cell volumes. The B1-WC hybrid functional was specially designed for ferroelectrics and systematically improves the calculated ferroelectric properties, however is computationally very expensive. Our results show that SCAN is comparable or more accurate than B1-WC but with much cheaper computational cost.
[1] Y. Zhang, et al., Phy. Rev. B 96, 035143 (2017)