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 from 7 countries across 3 continents.
This project is funded by the DMREF program from NSF (DMREF-1534503).
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).
Dielectrics under extreme electric fields: In situ studies on nanoscale mechanisms (led by Prof. Xiaoli Tan, Iowa State University)
Dielectrc breakdown is a major limiting factor for a number of applications in which materials are being exposed to strong electric fields, either because of high voltages, extremely thin layers, or a combination of the two. This work will utilize the unique capabilities of our collaborators (and project lead) at Iowa State University to observe the breakdown process in-situ at the nanoscale in a custom stage in a Transmission Electron Microscope. Our role is primarily to link the materials fabrication and processing to performance under large electric fields, both in the microscope and under more macroscale laboratory measurements.
Other projects include frequent collaborations on SBIRs, STTRs, and other industrial projects. We are also interested in (and in some cases, already working on) additive manufacturing of ceramics, inorganic perovskite photovoltaics, multicaloric ceramics, 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!