Beyond DFT First-Principles Description of 2D van der Waals Ferroelectrics

With the discovery of 2D van der Waals (vdW) ferroelectrics there is a renewed interest in their switchable and nonvolatile polarization for logic and memory applications. However, the same ferroelectrics can also host topologically nontrivial and tunable states [1]. With the growing family of these ferroelectrics there is a challenge to accurately describe their materials-specific properties. While density-functional theory is the common approach for the first-principles description of ferroelectrics, we show its various limitations and incorrect electronic structure, more pronounced in multi-layered systems. By focusing on In2Se3, as a prototypical 2D vdW displacive ferroelectric, we reveal how the shortcomings of DFT can be overcome within the framework of many-body Green function techniques.



[1] K. S. Denisov and I. Zutic, Moveable Dirac Points in 2D Ferroelectrics: Berry Dipoles and Kink States, preprint.