Abstract: In solid-state physics, conventional notions of the structure-property relationship correlate the atomic structure with macroscopic electronic properties. However, quantum materials often exhibit nanoscale order and heterogeneities deviating from the average structure. In this talk, we will quantify such deviations using the Bragg microscopy and discuss the impact of the heterogeneities on the material properties. Two examples will be discussed: persistent phonon dispersions due to the stacking disorder across the topological phase transition in a van der Waals material, and inhomogeneous electric field response from the self-assembly of polar nano domains in a ferroelectric relaxor. We will conclude the talk and discuss how nanoscale crystallography can provide critical insights into the structure-property relationship and accelerate the materials discovery and deployment in quantum information and microelectronics.

The work at Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division, through the Early Career Research Program.

Bio: Dr. Yue Cao is a staff scientist in the Materials Science Division at the Argonne National Laboratory. His research focuses on the emergent properties in a wide range of quantum and functional materials using cutting-edge X-ray methods. His recent interest lies in developing coherent and ultrafast X-ray approaches for understanding the material responses under the external electric and optical stimuli.

Dr. Cao obtained his B.S. from Tsinghua University in China in 2007, and his Ph.D. from the University of Colorado at Boulder in 2014. He was a postdoctoral research associate at the Brookhaven National Laboratory before joining Argonne as a staff member. Dr. Cao was an elected member of the User Executive Committee of the Linac Coherent Light Source between 2020-2023, and recently received the Early Career Award from the U.S. Department of Energy (DOE).