Large-Scale Molecular Dynamics Simulations of Ferroelectric Properties of Nanoparticles
Abstract
Purdue University Grant #: FA9451-16-1-0040 “Large-Scale Molecular Dynamics Simulations of Ferroelectric Properties of Nanoparticles” Abstract Ferroelectric materials are becoming increasingly important for logic and memory applications in nanoelectronics, actuators, photovoltaics, energy storage (e.g. capacitors) and signal transmission and modulation. Key to all these applications is an understanding of their response to electric fields, specifically the dynamics of ferroelectric switching. Transition temperature, domain structure and switching dynamics of these materials depend not only on composition but can also be engineered in thin films by an appropriate choice of substrate and orientation. Both experiments and molecular dynamics (MD) simulations have yielded significant information about atomistic processes that govern performance of these materials including the role of orientation in thin films. While notable progress has been made in understanding bulk and thin film samples, much less is known about ferroelectric transitions and switching dynamics in nanoparticles that can contribute significantly to the aforementioned applications. Given that switching in thin films is strongly affected by orientation and drawing an analogy to prior work on martensitic materials we hypothesize that switching in nanoparticles will show complex dependence on their shape and size as well as surface termination or passivation. Thus, the goal of this effort is to characterize ferroelectric domain structure and switching dynamics in nanoscale perovskites and use this knowledge to demonstrate the ability to engineer the properties of these materials. Specifically, we propose to study how size and shape affect ferroelectric performance in facetted and spherical particles of PbTiO3 and BaTiO3 including the role of surface passivation, solvent or matrix materials. Based on knowledge gained for simulations in homogeneous systems we will explore coherent core-shell structures designed to use interfacial strain to engineer the desired response. The proposed work will use ab initio electronic structure methods to characterize the fundamental surface energetics believed to dominate the response of nanoparticles and large-scale MD to characterize finite temperature dynamics including explicit simulation of ferroelectric transformation and field-induced switching.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 14, 2016
- Source ID
- FA94511610040
Entities
People
- Alejandro Strachan
Organizations
- Air Force Research Laboratory
- United States Air Force
- University of Virginia