Comparing Ab Initio Methods to Calculate Polarization for High-Throughput Screening of Ferroelectric Materials
Abigail Poteshman, University of Chicago
Ferroelectric materials exhibit spontaneous electric polarizations that can be tuned by applying external electric fields. These materials have applications in information storage and electronic devices. A material’s spontaneous polarization is often estimated using Born effective charges, which are calculated using density functional theory (DFT), along with atomic displacements relative to a nonpolar reference structure. For high-throughput screening to identify novel ferroelectric materials, however, a different approach, known as the DFT-based Berry phase method, has been used.1 This method accounts for the multivalued nature of polarization by interpolating between polar and nonpolar structures along a fictitious adiabatic path. Despite its success in identifying new candidate ferroelectrics, this interpolation-based approach encounters difficulties in properly distinguishing between different branches of polarization and when the fictitious, interpolated structures are spuriously metallic. Here, we compare these two approaches with a recently proposed method, known as Berry flux diagonalization. This alternative method directly computes differences in Berry phase from the wavefunctions of polar and nonpolar structures, thereby bypassing the need to calculate the Berry phase polarization of multiple fictitious, interpolated structures.2 We explore the run times, accuracy, and limitations of each method and discuss the implications for high-throughput screening of ferroelectric materials.
References:
1Scientific data 7 (1), 1-22 (2020).
2Phys. Rev. B 102, 045141 (2020).
Authors: Abigail N. Poteshman1, Francesco Ricci2-4, Jeffrey B. Neaton2,4,5
1Committee on Computational & Applied Mathematics, University of Chicago, USA
2Materials Science Division, Lawrence Berkeley National Laboratory, USA
3Chemical Science Division, Lawrence Berkeley National Laboratory, USA
4Department of Physics, University of California, Berkeley, USA
5Kavli Energy NanoSciences Institute at Berkeley, USA
Abstract Author(s): (see above entries)