Designing and Understanding Novel Phenomena in Ferroelectrics from First Principles
Abstract
The objective of this proposal is aimed at (1) understanding relaxor ferroelectrics and related materials at a microscopic level, inized physical responses, especially electromechanical, electronic and optical ones; and (3) revealing unusual and technologically-useful phenomena in functional ferroelectrics, such as non-linearelectro-optic effects and large dielectric and piezoelectric responses over a wide temperature range. This research program is highly relevant to national defense, since U.S. NAVY sonar-listening devices are made of ferroelectrics and since it can lead to the development of new generation of, e.g., data storage and communication devices. This objective will be achieved thanks to the development and use of the following state-of-the-art ab-initio numerical tools: (i) the accurate first-principles techniques, including total energy calculations, computation of phonon spectrum, modern theory of polarization and treatment of electric-field effects; and (ii) effective Hamiltonian approaches (also knownas second-principles techniques) that extend the reach of first-principles calculations by realistically mimicking finite-temperature static and dynamical properties of complex ferro-electrics (by using Monte-Carlo and Molecular Dynamics schemes, respectively). Collabo-rations with well-known international research groups having a vital experimental program on ferroelectrics will also continue to be strengthened, to ground our simulations and fully understand the systems to be studied.Various effects in many compounds will be investigated. Examples include the identification of the origin(s) of the huge piezoelectricity when doping Pb(Mg,Nb,Ti)O3 by rare-earth ions, and the puzzling existence of several polar phonon modes in Pb(Mg1=3Nb2=3)O3 relaxor ferroelectric. Another example is the design of large strain and control of electronic and optical properties when applying electric fields in the novel (Sc,Al)N ferroelectric, via structural deformations, and the discovery of new phases in brownmillerites (such as ns will be conducted to reveal and understand why the change of refractive index under electric field can have a non-linear behavior in BaTiO3 but not in Pb(Zr,Ti)O3 systems. The effect of strain and composition on the temperature broadening of physical responses will also be determined in lead-free (Ba,Ca)(Zr,Ti)O3 lms. Hyperferroelectricity and transient structural phases will also be studied. A deep microscopic knowledge of ferroelectrics will be gained and discovery of wunderbar" materials will occur, thanks to the diversity of the techniques, the variety of systems to be investigated, and the collaborations between University of Arkansas (UA) and other institutions specialized in ferroelectrics. These joint eorts will be the basis of a network for future collaborations. The granting of this proposal is also critical to continue to generate high-quality publications from, and bring international attention to, UA. Moreover, this proposal will not only tackle and understand real current material issues (such as microscopic features of relaxor ferroelectrics and of their large electromechanical response), but will also constitute one efficient theoretical explo optimized materials. The research program will be integrated into the educational experience of UA graduate and postdoctoral students. This experience is expected to be of substantial benefits to them both for knowledge-learning purposes, and for enhancing students ability to compete on thejob market { via the development of computer skills, interaction with experimentalists and visits to other institutions.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 02, 2021
- Source ID
- N000142112086
Entities
People
- Laurent Bellaiche
Organizations
- Office of Naval Research
- United States Navy
- University of Arkansas System