Brent Fultz, Rawn Professor of Materials Science and Applied Physics

    Fundamental materials physics and materials chemistry, with a view towards energy applications.



    Brief Biography and Research Summary

Brent Fultz received his undergraduate degree from MIT, and his Ph.D. from U. C. Berkeley in 1982. He was a Presidential Young Investigator, and he received an IBM Faculty Development Award and a Jacob Wallenberg Scholarship. More recently, he won the 2010 TMS EMPMD Distinguished Scientist Award, the. 2016 William Hume-Rothery Award of TMS. He was elected Fellow of the Neutron Scattering Society of America in 2016, full member of the Society of Sigma Xi in 2017, Fellow of the American Physical Society in 2017, Fellow of TMS in 2018, and was chosen as an "Outstanding Referee" by the American Physical Society in 2019. He serves on review boards of the Advanced Photon Source and the Spallation Neutron Source. He consulted for an electronics testing company, Everett Charles Technologies, for the Defense Science Board, was a member of the Science Advisory Board of Actium Materials, Contour Energy, and the Materials Project. Fultz has authored or co-authored approximately 400 publications.

With his friend, Prof. J. Howe of Univ. Virginia, Fultz published a graduate-level textbook on diffraction and microscopy of materials (now in its fourth English edition, first Russian edition, and under translation into Chinese). More recently, Fultz authored a graduate-level textbook on phase transitions in materials that unifies concepts from traditional materials science and from condensed-matter physics.

X-ray and neutron scattering are two of the most important methods for studying materials, and the U.S. community of scattering scientists now has access to remarkably powerful and precise synchrotrons and neutron sources. These require innovative hardware and software for new studies of materials. Brent Fultz was the Principal Investigator for building the ARCS spectrometer at the Spallation Neutron Source, in operation since 2007. Scientific computing offers opportunities for doing new science with neutron scattering experiments, and Brent Fultz was the Principal Investigator of the software project Distributed Data Analysis for Neutron Scattering Experiments, DANSE, that took advantage of opportunities described in this workshop report website.

One topic of Fultz's research is how atom vibrations in solids affect the entropy and free energy of materials -- a review article is available here (4.5 MB). Vibrations are the main source of entropy of solid materials. They are quantized as "phonons," which we measure by inelastic neutron scattering. Inelastic neutron scattering is also sensitive to magnetic and electronic excitations in solids, and these excitations can have thermodynamic importance, too. An important scientific challenge is to identify the reasons why different materials have different phonon entropies, and how phonon entropy changes with temperature and pressure. Recent work has focused on behavior over a broad range of temperature, where phonons interact with other phonons, and with electronic excitations. Future work will emphasize new effects that arise with simultaneous temperature and pressure.

Modern ab initio computations based on density functional theory are now essential for work on phonons and electrons in solids. In practice, high pressure research is generally easier by computation, and high temperature work is generally easier by experiment. Nevertheless, at high temperatures, the quasiparticle excitations of phonons and electrons can be studied computationally by ab initio molecular dynamics. Using high-resolution inelastic x-ray scattering, Fultz's group has also been measuring how vibrational thermodynamics is altered when the material is under megabar pressures in a diamond anvil cell.

The global "energy problem" is of paramount societal importance, and of some urgency. For many years Fultz's group has worked on materials that store lithium (used in rechargeable batteries), and on materials that store hydrogen. One effort is focused on understanding the interactions of hydrogen molecules with surfaces, with the goal of learning how to optimize the hydrogen-storage potential of new materials that store hydrogen by adsorption interactions. For materials that store lithium or sodium ions, Fultz's group found an opportunity to use nuclear resonant scattering on materials at sub-megabar pressures to measure the atom distortions that occur as an electron hops between adjacent ions. The mechanism of "small-polaron hopping" is the source of electrical conductivity of many battery materials that are otherwise insulators at low temperatures. Understanding polaron dynamics should open possibilites for many more electrode materials in rechargeable batteries.

Brief descriptions of recent research results are given in the Fultz Group site. Fultz's interview for the Distinguished Scientist Award, with thoughts for young scientists, is here.