Year: 2024
Type: article
Abstract: MnBi₂Te₂ is a magnetic topological insulator with layered A-type antiferromagnetic order. It exhibits a rich layer- and magnetic-state dependent topological phase diagram; however, much about the coupling between spin, charge, and lattice remains to be explored. In this work, we report that MnBi₂Te₂ is an excellent acoustic phonon cavity by realizing phonon frequency combs using picosecond ultrasonics. With the generated acoustic phonon wavepackets, we demonstrate that the timing and phase of acoustic echoes can be used to detect the presence of stacking faults between van der Waals layers buried deep within the crystal. Furthermore, by implementing this nondestructive ultrafast optical measurement in conjunction with time-resolved magneto-optical Kerr effect experiments, we uncover that out-of-plane vibrations in MnBi₂Te₂ do not couple to the magnetic order, i.e. there is no appreciable magnetostriction. Our work points out how a well-developed technique can probe the structural defects and phonon pulse engineering in layered topological insulators.
DOI: 10.13016/m23pmg-ydrd
Authors: Fonseca, Jordan, Diederich, Geoffrey M., Ovchinnikov, Dmitry, Yan, Jiaqiang, Xiao, Di, Xu, Xiaodong
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, University of Washington, Office of the Director of National Intelligence, Office of Science, Oak Ridge Institute for Science and Education, Clean Energy Institute, Intelligence Community Postdoctoral Research Fellowship Program, Materials Research Science and Engineering Center, Harvard University, Division of Materials Research, Basic Energy Sciences, Air Force Office of Scientific Research
OpenAlex ID: W7082270970