Computation Of Undiscovered Piezoelectrics and Linked Experiments for Design (COUPLED)
By teaming up with colleagues from NREL and from across Mines, we are combining high throughput computation with combinatorial experimental techniques to discover and develop new piezoelectrics with a specific focus on nitride materials. The computational efforts are led by Cristian Ciobanu and Vladan Stevanovic, while the complementary experimental efforts are up to our group along with Corrine Packard and our close NREL collaborator, Andriy Zakutayev. With all of the data produced by these efforts, we need help making sense out of the large, sparse, and heterogeneous datasets... Paul Constantine to the rescue! Finally, in order to assist rapid transition of newly developed materials and/or processes to commercial relevance, we have an industrial advisory board that currently consists of representatives from 18 partner companies.
This project is funded by the DMREF program from NSF (DMREF-1534503).
Integration of High-Performance Ceramic Capacitors with Low-Cost Copper Electrodes via Advanced Kinetic Control
A number of applications demand capacitors which can work at temperatures above 150C and offer higher capacitance, energy density, resistivity, and reliability at lower costs than currently-available options. Dielectrics in the BaTiO3 - Bi(M)O3 family, where M represents a trivalent or trivalent-equivalent combination of B-site ions, look very promising for such operating conditions, but in order for them to be commercially viable in large volumes, they must be integrated with low-cost electrodes. We are working with local partner Pneumaticoat Technologies to develop technology that will enable us to integrate BaTiO3-Bi(Zn,Ti)O3-based dielectrics with low cost Cu electrodes. In addition to the application-driven engineering aspect of this project, we are also trying to develop a better understanding of the unusual polarization mechanisms, defect chemistry, and overall processing of these materials.
This project is funded by the Colorado Office of Economic Development and International Trade.
Dynamic Defect Interactions in Ferroelectrics
Ferroelectrics are defined by the reversal of their spontaneous polarization under an applied electric field, a process that occurs via nucleation and growth processes. Despite significant advances in theoretical descriptions and measurement/characterization techniques, the dynamic response of a ferroelectric to an applied electric field is still typically described in terms of an empirical relationship first reported by Merz in 1954. This project aims to better understand and quantify the interactions among defects, interfaces, and ferroelectric domain walls. The fundamental question at hand is, “What constitutes a domain pinning vs. nucleation site?” Understanding pinning (essentially speed bumps in the way of propagating domain walls) and the nucleation process are both crucial to improving the performance of ferroelectric and piezoelectric materials across a number of applications, particularly under high power drive conditions where deviations from the classic empirical model are often significant. We are approaching this by attempting to isolate crucial variables in order to identify the independent contributions of point defects, grain boundaries, and other types of interfaces.
This project is funded by the Ceramics program from NSF (DMR-1555015).
We are also interested in (and in some cases, already working on) Pb-free piezoelectrics, phonon-photon interactions, many types of emergent phenomena in complex oxides and nitrides, entropy-stabilized oxides, growth and characterization of oxide single crystals, integration and clever processing of thin film ferroelectrics and piezoelectrics, and advanced ceramics processing of all types. Please contact us to learn more, collaborate, and/or just discuss fun ceramics ideas!