Quantum materials have the potential to transform technology just as transistors did, but before that can happen scientists have to understand how their components interact—and how those interactions are manifested. UT’s physicists and their colleagues were asked for their expertise on how one experimental method can play a defining role in those discoveries. 

UT Physics Bains Professor Steven Johnston and Adjunct Professor Mark Dean (a physicist with the distinction of tenure at Brookhaven National Laboratory), along with their colleagues Matteo Mitrano (Harvard University) and Young-June Kim (University of Toronto), have published an authoritative perspective piece in Physical Review X on applications of resonant inelastic x-ray scattering (RIXS) to quantum materials.

PRX Perspectives judiciously survey and synthesize existing fields with a forward-facing outlook on how the technique can address significant questions for the field and are commissioned by the journal’s editors. The article “Exploring quantum materials with resonant inelastic x-ray scattering” marks the third in the series since its launch in 2022.

Understanding quantum materials—solids in which interactions among constituent electrons yield many novel emergent quantum phenomena — is a forefront challenge in modern condensed matter physics. This Perspective article highlights the potential for RIXS, which has experienced rapid growth as a probe of quantum materials, to explore these novel materials. Progress in instrumentation means that we are now at a watershed period of being able to apply RIXS with time and energy resolutions that match the fundamental energy scales of many quantum materials and solve key problems in this major area of condensed matter physics.

The article is available through open access and can be downloaded at  https://journals.aps.org/prx/abstract/10.1103/PhysRevX.14.040501.

–Courtesy of Bains Professor Steven Johnston

Above: The Kramers-Heisenberg process for resonant inelastic x-ray scattering (RIXS) and the different excitations that it can probe. The RIXS process, shown in the center, involves the resonant absorption of an x-ray photon, creating an intermediate state with a core hole and a valence excitation, before the hole is filled via the emission of another x-ray photon. By measuring the energy and momentum change of the x rays, one can infer the properties of the excitations created in the material. Around the outside, we illustrate the many different types of excitation that RIXS can probe, arranged clockwise in order of increasing energy scale, as denoted by the red-to-blue circular arrow.