June 9
@
2:30 PM
–
3:30 PM
UW-Madison Department of Materials Science and Engineering welcomes Dr. Angela R. Hight Walker. Her seminar, “Novel Instrumentation for 2D Material Characterization: Combined Helicity-Resolved Magneto-Optical with Magneto-Transport”, will take place on Tuesday, June 9, 2026, from 2:30-3:30 p.m. in MSE 265.
Bio
Dr. Angela R. Hight Walker is a senior scientist at the National Institute of Standards and Technology (NIST), recognized for her leadership in pioneering optical spectroscopies to characterize quantum materials. A current focus area is using optical signatures to study magnetic order. Over three decades, she has led a dynamic research team unraveling the complexities of low-dimensional materials, contributing nearly 200 multidisciplinary publications at the inface of physics, chemistry, and materials science. She is a Fellow of the American Physical Society (APS) and the American Association for the Advancement of Science (AAAS) and OPTICA. Dr. Hight Walker is also a leading figure in nanotechnology standardization efforts, contributing to ISO Technical Committee 229 Nanotechnologies and VAMAS TWA 41 and 42 committees. Beyond her scientific achievements, Dr. Hight Walker is deeply committed to fostering inclusivity and diversity in science. She just finished the Chair-line for the Committee on the Status of Women in Physics (CSWP), one of APS’s oldest committees. She boldly advocates for science accessibility, engaging young and under-resourced individuals through demonstrations and lectures, while mentoring over 50 students and postdoctoral researchers, many from underrepresented groups.
Abstract
Raman spectroscopy, imaging, and mapping are powerful non-contact, non-destructive optical probes of quasiparticles and fundamental physics in graphene and other related two-dimensional (2D) materials, including layered, quantum materials. An amazing amount of information can be quantified from the Raman spectra, including layer thickness, disorder, edge and grain boundaries, doping, strain, thermal conductivity, magnetic ordering, and unique excitations such as magnons and charge density waves. Most interestingly for quantum materials is that Raman efficiently probes the evolution of the electronic structure and the electron-phonon, spin-phonon, and magnon-phonon interactions as a function of laser energy and polarization, temperature, and applied magnetic field. Our unique magneto-Raman spectroscopic capabilities will be detailed, enabling polarization- and spatially-resolved optical measurements while simultaneously measuring electrical transport in a back-gated graphene Hall bar device.Raman and electrical data from an hBN-graphene-hBN device operating in the quantum Hall regime will demonstrate our novel capabilities. Also, results from a series of 2D magnetic material systems showing multi-quasiparticle interactions observable with our unique measurement system will be highlighted. Lastly, the importance of detailed alignment, calibration and reference materials will be demonstrated quantifying the ability to differentiate chiral phonons as a function of temperature and laser wavelength.