NSLS-II User Profile: Geneva Laurita, Bates College
In the "Leading Lights" series, visiting researchers sit down with NSLS-II staff for a Q&A on their research and user experience
May 12, 2021
Geneva Laurita
Geneva Laurita is an assistant professor of chemistry and biochemistry at Bates College, a private liberal arts college based in Lewiston, Maine. Her research is focused on inorganic materials for energy and electronics applications. To investigate the structure-property relationships of these materials, Laurita leverages the high energy x-rays, rapid data acquisition rates, and advanced research techniques available at the National Synchrotron Light Source II (NSLS-II)—a U.S. Department of Energy (DOE) Office of Science User Facility at DOE’s Brookhaven National Laboratory.
What scientific questions drive your research?
I consider myself to be a solid-state chemist, so I’m interested in researching the structure-property relationships of a variety of solids, but I spend most of my time researching crystalline materials for energy and electronic applications. By studying the arrangement of individual atoms in those materials, we can learn how they interact with external stimuli like light and electricity. In other words, by determining the atomic-scale structure of these solids, we can understand how they might conduct electricity, for example, and how we can tune those properties for more efficient and sustainable applications.
One effect that I’m particularly interested in is called the piezoelectric effect, which enables materials to convert between mechanical and electrical energy. A common example of this effect is in a lighter, which has a piece of quartz that can be struck to create a spark and light the gas. Another example of the piezoelectric effect is how smartphones can rotate their display. Smartphones contain a tiny crystal, and when you turn your phone on its side, gravity applies a mass in the phone onto the crystal. That mechanical pressure sends a voltage to your phone, signaling the display to orient in the opposite direction. There are also a lot of devices that use the piezoelectric effect in the reverse way, applying a voltage to generate a mechanical effect, like expanding the size of a crystal.
What specific materials are you researching right now?
The biggest project I have right now aims to discover new polar materials for electronic applications. One of the major issues with our current polar materials—materials that do not have a symmetric distribution of their electron cloud—is that they use lead. Lead is found in many electronics because it has some great chemical properties, including a stereochemically active lone pair, which distorts its molecular environment and makes it a good polar material. But lead is also a toxic material. If we think about the complete lifecycle of electronics, from making and harvesting the materials to disposing of the electronics after we’re finished with them, we need to consider more sustainable solutions. I’m trying to find and understand the structure of new polar materials that don’t have lead but have similar electronic properties.
What types of experiments do you typically conduct to investigate the structure of these materials?
I typically conduct a combination of x-ray and neutron studies because each method can reveal different information about a material. The combination can give you a really great view of the structure as a whole.
Why did you choose to come to NSLS-II for your x-ray studies?
One of the big things that I’m interested in is the idea of disorder within crystalline materials. Crystalline materials generally have a really nice repeating unit of atoms, but a lot of the properties I’m looking at arise from disorder, or where there is deviation from perfect symmetry. To study this type of structure, I need NSLS-II’s high energy x-rays. I can’t do this type of research with my x-ray diffractometer here at Bates. That instrument enables me to confirm I’ve synthesized the right structure, but I can’t retrieve more detailed data beyond that.
Specifically, I use the Pair Distribution Function (PDF) beamline at NSLS-II, which is optimized for the type of scattering experiment I need to conduct, also called pair distribution function analysis. Pair distribution function analysis is really useful for understanding the very local coordination environment around atoms, but it also has more advantages over other techniques, because you can not only see what’s happening with the immediate “neighbors” of an atom, but also its next nearest neighbors and the next nearest neighbors and so on. With this technique, you can study how different atoms are interacting with each other over different length scales and you would miss that in other techniques.
NSLS-II’s high intensity beam is also great for collecting a lot of data. I typically collect data once or twice a year at NSLS-II, and that gives my students and I enough data to analyze for the entire academic year or longer.
What was your experience like with the beamline staff?
It’s always fantastic to work with the beamline staff at NSLS-II, no matter who I’m working with. They’re always interested and invested in my science, but they’re also really helpful on a personal level, like helping me get my security badge to gain access to Brookhaven. They’re invested in the science but they’re also invested in the users, making the experience as fun and smooth as possible.
The beamline staff are always available for a pre-planning period during which we discuss how we want to collect and analyze the data. When I come on site, they also give me a training session to learn how to use the instrument, they’ll come in and check that my experiment is running correctly, and they’ll help me throughout the entire process. Even when I conduct experiments remotely, there is help every step of the way. During my last remote experiment, I was able to see the beamline scientist set up the entire experiment and we could watch it run on the computer together. With remote experiments at NSLS-II, it’s not just a black box that you’re sending your samples to.
You mentioned your students are working with the data you collected at NSLS-II. To what extent are students involved in your research?
Every student at Bates conducts a year-long research thesis project, so I typically have about four or five thesis students a year and they are all actively collaborating with me on my research. In fact, all five of my students this year are currently using data from NSLS-II in their thesis right now!
I started doing this kind of research when I was an undergrad, so continuing to ignite that undergraduate passion is something I strive to do. There’s something really invigorating about working with brand new scientists who are still finding their identity. I feel like I hit the jackpot at Bates. I get to do a lot of cool research with my students and I have never felt like being at an undergraduate institution has stifled the quality of my research.
NSLS-II and the national lab system as a whole play a major role in shaping the quality of my research and my community in general, recognizing and reinforcing the idea that good research can still be done with undergraduates. When my students get to visit NSLS-II and interact with the beamline scientists, it gives them purpose behind the science. They can see that what they’re doing in class can become a career. The experience creates a connection and excitement for them. Seeing the students’ faces when they visit facilities like NSLS-II is why I do what I do.
Brookhaven National Laboratory is supported by the U.S. Department of Energy’s Office of Science. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science.
