Symmetry Effect on Phonon Wave Propagation

From a six-fold snowflake to a bird feather, symmetry exists ubiquitously in nature. In this talk, I will discuss how different symmetries influence mechanical vibrations, i.e., phonons, in 1D and 2D structures. In the first part of my talk, I will discuss the role of glide reflection symmetry in quasi-one-dimensional beams. We will use a periodic sandwich beam as an example to demonstrate how a glide-reflection symmetry can benefit the design of sandwich beams to mitigate vibration effectively. Then I will introduce how to use topological invariants derived from the bulk properties to determine the dynamic characteristics at the edges and corners in 1D and 2D lattices. The fundamental understanding of phonon wave manipulation obtained from this study is not only important in the well-explored acoustic sensing and thermal management applications but also offers the potential to advance quantum information processing technologies, such as quantum computing.

Jihong Ma is an Assistant Professor in the Department of Mechanical Engineering at the University of Vermont. Dr. Ma obtained her PhD in Mechanical Engineering from the University of Minnesota-Twin Cities in 2017 and her BEng in Engineering Mechanics from Xi’an Jiaotong University (China) in 2012. Her PhD thesis focused on computational heat transport in nanomaterials. She then worked as a Postdoctoral Associate in the Department of Civil, Environmental, and Geo- Engineering at the University of Minnesota-Twin Cities, studying topological metamaterials from 2017 to 2019, and at Oak Ridge National Laboratory - Center for Nanophase Materials Sciences from 2019 to 2020, working on polymer dynamics. At the University of Vermont, Dr. Ma is working on the structure-property relationship of a variety of materials at multiple scales (from nano- to macro-) via a combination of theoretical analysis, numerical simulations, and experimental characterizations. Her current active research projects include investigations of self-healing polymers, polymeric membranes for carbon capture, organic electronics, quantum dots, dynamics of phononic crystals, and nanoscale thermal and electrical transport. Her research is being supported by various funding agencies, including the National Science Foundation, the U.S. Department of Energy, NASA, and the Semiconductor Research Corporation. She is an Air Force Research Laboratory Summer Faculty Fellow in 2023.