Dr. Mourigal joined Georgia Tech in 2015 as an assistant professor in the School of Physics. Prior to joining Georgia Tech, he completed a three-year postdoctoral research fellowship at the Institute for Quantum Matter at Johns Hopkins University in Baltimore, Maryland. He earned his PhD in experimental physics jointly from the Institut Laue-Langevin in Grenoble, France and École Polytechnique Fédérale de Lausanne in Lausanne, Switzerland. His research interests combine materials characterization, neutron scattering, data analysis and theory to explore novel magnetic and electronic states of quantum matter.
What brought you to Georgia Tech?
First, a vigorous program in condensed matter and materials physics and the geographic proximity (a short three hours drive) to Oak Ridge National Laboratory’s world-class neutron sources, namely the Spallation Neutron Source and the High Flux Isotope Reactor. My research aims at understanding how microscopic quantum effects between electrons transcend the atomic-scale and lead to new materials properties such as magnetism and superconductivity. Because these phenomena are truly collective and involve complex correlations between a very large number of electrons they are usually difficult to describe theoretically. Neutrons can probe magnetism deep inside materials and provide a unique glimpse on how electrons organize and vibrate at the nanoscale. To accelerate discovery with neutron scattering it is paramount to find and characterize new materials, grow high quality samples and connect experimental results with the latest theoretical ideas. Having a state-of-the art laboratory to do that on campus is a great asset. Finally, I was always attracted to the idea of teaching and that was an important factor in my pursuit of a faculty position at a university rather than scientist at a national laboratory or in industry.
Explain the energy applications of your work.
While my work is primarily a fundamental endeavor, consequences and potential applications for energy are enormous. By understanding how matter is organized at the nanoscale and responds to perturbations, we are writing the basic dictionary relating microscopic structure to macroscopic properties. In the spirit of the “Materials Genome Initiative”, this is a first and crucial step to engineer materials with desirable and controllable properties such as better batteries, more efficient solar cells, intelligent multiferroic materials or novel thermoelectrics. Another driving force for my research is the understanding of high temperature superconductivity. In superconductors, electrons flow without any resistance. Domesticating this property will have a transformative impact on the way we harvest energy and construct a reliable electric grid at the scale of a continent such as North America. The challenge is that in most materials, superconductivity only shows up at very low temperatures. In 1986 and then in 2008, novel “high temperature” (but still way below room temperature) superconductors were discovered and contain magnetic copper and iron, respectively. The fundamental physics of these materials is extremely rich and complex as charge, spin, orbital and lattice degrees of freedom intimately interplay. By looking at magnetic materials that are cousins of the high-temperature superconductors we hope to contribute to a community-wide effort to solve this mystery.
What role can quantum materials play in addressing key energy science and technology challenges?
Quantum materials are appealing because they host tunable quantum coherence effects. A central challenge is to bring these phenomena to human length and time scales. I am convinced this pursuit will lead to radically new technologies such as the advent of quantum computing. One of the concept we are working on in the lab is that of “quantum spin-liquids”, exotic states of magnetic matter where electrons’ spins are entangled over long distances. In his critique of quantum mechanics, Einstein’s famously called entanglement “spooky action at a distance”. Physicists realized that understanding and manipulating long-range entanglement could have enormous consequences for cryptography and decoherence-free quantum computing. Among other things, quantum computers have the potential to predict the behavior of high-temperature superconductors or bio-chemical assemblies that are simply to complex to simulate on classical computers. From the iron-age to the silicon-era, human development is intimately linked with the discovery and control of new classes of materials to harvest and distribute energy and information. I hope that the rise of quantum materials will help humans address the grand challenges of global warming, resource inequality and health.
Most exciting recent energy-related quantum physics discovery and why?
A lot of recent serendipitous discoveries are particularly exciting. One example is the discovery of superconductivity at -70C in extremely high-pressure hydrogen sulfide. -70C can actually occur on the surface or Earth! However, I think one of the most exciting recent breakthrough in quantum physics is the prediction and experimental observation of numerous “topological states of matter”. Topology comes from mathematics and in Layman terms is a way to classify objects according to their global shape rather than local properties. For instance, a football is topologically distinct from a doughnut because a doughnut has a hole. But footballs used in the US (elongated) and in the rest of the world (round) are topologically equivalent. Now, in quantum materials electrons describe complicated orbits and it turns out that the language of topology can be used to classify these orbits (also called band- structures). This was known for quite a while but researchers only recently realized that some exotic “topological” materials are like doughnuts while most other materials are like footballs. Topological materials have interesting properties such as the ability to conduct electricity only at their surface. The amazing thing is that these properties are guaranteed to occur and survive even in presence of disorder or chemical imperfections because they come from a global rather than local physical principle. The consequences of this “Eureka!” moment in topology are still being explored today but I have not doubt topological materials will be a game changer to produce more reliable devices and technologies.
If you were not teaching or conducting research, what would you be doing?
My path to physics and to a faculty position was not straight although I became really interested in physics from high school on. I wanted to be an air-traffic controller in France but a minor vision condition prevented me from taking that job and I had to change plans. Through a series of lucky “scattering” events I ended up here at Georgia Tech doing physics! I like to think about abstract ideas and realize them in practice so a career in Architecture would have been fun too.