Hierarchical multiscale modeling of flexoelectricity and related materials properties from first principles
Flexoelectricity, the coupling between an inhomogeneous deformation and the electrical polarization, has emerged a “hot” topic in modern materials science due to its cross-cutting relevance to many phenomena of fundamental and technological interest. Understanding the intriguing physics that governs its behaviour at the nanoscale is crucial to harnessing the potential of strain gradients in practical applications, and such a progress requires a substantial support from theory. In spite of impressive recent advances, first-principles calculations of flexoelectricity remain technically challenging at several levels: first, the breakdown of translational lattice periodicity that a strain gradient entails is problematic to treat in the context of traditional electronic-structure methods; second, the stringent length- and time-scale constraints of direct quantum-mechanical approaches limit the applicability of these methods to real problems, which often involve complex sample shapes and morphologies. This project is aimed at overcoming these obstacles from their very root, via the development of ground-breaking innovations in electronic-structure and multiscale methodologies, and at using these advances to address a number of pressing physical questions in the context of energy and information technologies. In particular, the objectives of this project are: (i) identifying the microscopic mechanisms that are most effective at delivering a strong flexoelectric response in a variety of materials; (ii) understanding how these bulk effects are modified by size, shape and boundary conditions, and how they interact with other material properties; (iii) supporting the experimental interpretation by critically assessing alternative physical interpretations of the observed effects (e.g. compositional gradients); (iv) exploring the functionalities enabled by strain gradients in complex materials systems, including 2D crystals, semiconductor nanowires and multiferroics.