Sparse Big Data Spectromicroscopy on Magnetic Quantum Materials

New York University, New York NY

Investigators

Abstract

Non-Technical Abstract Spectroscopy at synchrotron X-ray facilities is often used to observe the quantum states of electrons inside materials, and can yield critical insights for quantum science and technology. Over the last decade, a new generation of synchrotron technology has begun to greatly increase capabilities for focusing X-ray beams down to microscopic scales. The measurements this enables are termed ‘spectromicroscopy’, and can give far clearer images of electronic states by excluding any structural or chemical variation that occurs outside the measurement area. In these investigations, the research team is applying spectromicroscopy to uncover the electronic states within structurally complex quantum materials that feature exotic magnetic properties and may be of use for advanced information technologies. Whereas traditional spectroscopy measurements look at just one or two spots on a material, this research develops new capabilities to rapidly survey naturally occurring regional differences across large patches of the sample surface. These variations are analyzed to better understand the big picture of how functional material properties can be controlled if you change the chemical ingredients or material growth procedure. Technical Abstract Recent progress in light source technology is driving the worldwide development of beamlines with highly focused micron- and 100-nanometer-scale beam spots. This project uses spectromicroscopy implementations of the angle resolved photoemission and resonant inelastic X-ray scattering techniques to uncover the electronic structures underlying core properties of interest within selected magnetic quantum materials. Particular focus is given to cases that have presented challenges to the previous generation of spectrographs, such as select topologically ordered materials that incorporate magnetic elements. A key factor in achieving this ambitious goal is the use and further development of a suite of techniques for analyzing sparse big data sets from measurements in which a beam is rastered rapidly over a sample surface while recording spatially resolved spectra. This approach simultaneously minimizes beam damage and makes it possible to catalogue the regional variability of the electronic structure, to identify the nontrivial interplay phenomena caused by quantum hybridization and strong correlations. Algorithms and software created to address these analysis challenges are made available to the broader spectroscopy community. The research activities on advanced materials are integrated with facility tours and other outreach for local K-12 students. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.