Electromechanical properties of layered perovskite oxide ferroelectrics from first principles
Abstract
Identifying new high-performance piezoelectric and ferroelectric materials is key for developing next-generation Navy technologies, such as sensors and SONAR. A strong electromechanical coupling, that is, a link between the electrical (electric polarization) and mechanical (stress/strain) properties of materials is a key ingredient for these technologies. The objective of this ONR Proposal is to identify strategies to realize novel and enhanced electromechanical effects, focusing on a family of recently discovered layered perovskite oxide ferroelectrics. These layered perovskites do not contain lead and operate at room temperature, so they are very pr omising for integration into applications. Traditionally, efforts to obtain large electromechanical responses have focused on increa sing the magnitude of piezoelectric coefficients of bulk piezoelectric materials. Here, we propose to leverage the unique aspects of layered perovskite oxides to explore two alternative strategies for obtaining enhanced electromechanical responses. First, we will harness the large number of structural phases that compete for the ground state in layered perovskites to identify pathways to stabi lize these materials in an antiferroelectric state, where there is a non-polar ground state and a metastable polar phase slightly hi gher in energy. We propose that phase transitions between these non-polar and polar phases, induced by application of an electric fi eld or mechanical stress, are a mechanism to obtain enhanced electromechanical response. Second, we will explore layered perovskite oxide ferroelectrics in freestanding membrane form as a novel piezoelectric platform. We will investigate whether recently reported extreme strain states in oxide membranes can be harnessed to yield enhanced electromechanical responses. This theoretical and comp utational research program will utilize a combination of group theoretic symmetry analysis and density functional theory calculation s. The ideas developed in this research will be tested and refined through collaboration with the PIs network of experimental colla borators, who both synthesize and characterize layered perovskite materials.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 22, 2021
- Source ID
- N000142112957
Entities
People
- Elizabeth Nowadnick
Organizations
- Office of Naval Research
- United States Navy
- University of California