Moore quantum materials: Recipe for serendipity

Moore Foundation grant will allow Rice physicist to explore quantum materials

Thanks to a $1.5 million innovation award from the Gordon and Betty Moore Foundation, Rice University physicist Emilia Morosan is embarking on a five-year quest to cook up a few unique compounds that have never been synthesized or explored. Morosan is no ordinary cook; her pantry includes metals, oxides and sulfides, and her recipes produce superconductors and exotic magnets.

Morosan, associate professor of physics and astronomy, of chemistry and of materials science and nanoengineering, has been named a Moore Foundation Materials Synthesis Investigator. Her lab specializes in the design, discovery and synthesis of compounds with unconventional electronic and magnetic ground states. She said the Moore funding, which was provided through the foundation’s Emergent Phenomena in Quantum Systems Initiative, allows the freedom for experiments that might cause other funding agencies to balk.

Emilia Morosan

“For many years, the United States was the undisputed leader in materials synthesis, but governmental funding has fallen dramatically at a time when Europe and Asia have invested heavily,” Morosan said. “With this new initiative, I think the Moore Foundation is filling a stringent need for more exploratory materials synthesis research that doesn’t fit with the well-defined rationale of traditional funding agencies.”

Morosan stressed that her research is focused on elucidating the fundamental properties of materials with emergent behavior.

“I know it can be a turnoff when people ask, ‘What is this good for?’ and we say, ‘This is more fundamental than applicable,'” she said. “But at the root of all engineering applications is some fundamental concept that was discovered and that was only applied after a library of knowledge was built up around that and many other discoveries.”

Morosan is well-aware that the initial act of scientific discovery can involve serendipity — the “failure” of synthesizing a never-before-seen compound while targeting a totally different one. That happened in her lab in 2009.

Following the discovery of the first iron-based high-temperature superconductors, Morosan’s group was attempting to make a compound of cerium, iron and arsenic that contained a ratio of 1-2-2 — one cerium ion to each two iron and two arsenic ions.

Many quantum materials often have similar compositions, even when the elements differ. For example, the discovery of the first “heavy fermion” in 1979 — a find that preceded high-temperature superconductivity by seven years — contained one ion of cerium for two copper and two silicon ions. This 1-2-2 ratio has been found repeatedly over the years in many other quantum materials, including other heavy fermions as well as high-temperature superconductors.

Morosan and her team knew something was amiss as soon as the 2009 synthesis was completed.

“What we were trying to make should have looked like plate crystals,” she said. “What we ended up with were needle-like crystals.”

Upon further examination, her team learned that their mystery material had both intriguing physical properties and a hitherto unreported 1-4-3 atomic ratio. The structure remains unique; it has yet to be found in another compound, despite years of worldwide effort.

Morosan said the Moore funding will allow her to pursue several lines of research, and one of these will be a “fishing expedition” that aims to systematically explore whole families of little-studied materials. She said the hope is to combine knowledge, intuition and technical skill to help foster the chances for serendipity.

“There are phase spaces and materials families that have been overlooked for years, for a variety of reasons,” she said. “I think there’s a lot to be found at the bottom of the sea, in these unexplored places.

“It is a gamble because I don’t know if these compounds will form, and if they do, I don’t know if the physics will be interesting. But if I’m allowed some freedom to try, then I am confident we will learn a great deal and will find really interesting new physics. And even if we don’t, and we simply make progress toward answering some of the critical questions in condensed matter physics, then it will still be a success.”