Ultrafast-induced Coherent Acoustic Phonons in the Two-dimensional Magnet CrSBr

ORAL

Abstract

CrSBr is an air-stable, novel two-dimensional (2D) magnetic van der Waals (vdW) single crystal that received intense study as a future spintronics material. The material shows some interesting properties such as a large optical band gap (~ 1.5 eV), strong spin-phonon coupling (SPC) effect, quasi 1-D electronic structure, strain-induced magnetic phase transitions, and enhanced structural deformability. In our work, mega-electron volt (MeV) ultrafast electron diffraction (UED) was employed to investigate the ultrafast structural dynamic response of this material. We observed femtosecond pump pulses excited small anisotropic lattice deformations that are to be mediated by coherent acoustic phonons (CAPs). The phonons were interpreted as longitudinal breathing modes. The ultrafast oscillatory behavior of Bragg peak intensities was simulated by incorporating an oscillating deviation parameter ansatz into dynamical scattering intensity expressions. The phonon frequencies were extracted by analyzing these oscillations in Bragg peak intensities and they were in nearly 23 GHz range. These results suggest a promising path for tuning the ultrafast photo-induced properties of CrSBr with sample geometry and dimension.

* This work has been supported by Brookhaven Science Associates under Contract No. DE-SC0012704 with the U.S. Department of Energy, Office of Science, and the U.S. Air Force Office of Scientific Research and Clarkson Aerospace Corp. under Award FA9550-21-1-0460. B.F. acknowledges Welch Professorship support from the Welch Foundation (Grant No. L-E-001-19921203) and the Texas Center for Superconductivity at the University of Houston (TcSUH). A.M.R. and J.J.B. acknowledge the support from European Union (ERC-2021-StG 101042680 2D-SMARTiES awarded to J.J.B.), the Spanish MICINN (Excellence Unit María de Maeztu CEX2019-000919-M), and the Generalitat Valenciana (CDEIGENT/2019/022); A.M.R. thanks the Spanish MIU (Grant No FPU21/04195). The work at the University of Washington is supported by AFOSR FA9550-19-1-0390 and FA9550-21-1-0460.

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Publication: Ultrafast-induced Coherent Acoustic Phonons in the Two-dimensional Magnet CrSBr (The manuscript is ready to submit)

Presenters

  • Jayajeewana Niranjana Ranhili Pelige

    University of Houston

Authors

  • Jayajeewana Niranjana Ranhili Pelige

    University of Houston

  • Byron Freelon

    Department of Physics and Texas Center for Superconductivity, University of Houston, University of Houston

  • Sumit Khadka

    Department of Physics and Texas Center for Superconductivity, University of Houston, University of Houston Chapters

  • Junjie Li

    Brookhaven National Laboratory

  • John Cenker

    University of Washington

  • Xiaodong Xu

    University of Washington

  • Alberto Ruiz

    University of Valencia

  • José Baldoví

    University of Valencia

  • Ka Shen

    Beijing Normal University

  • Mikhail Fedurin

    Brookhaven National Laboratory

  • Mark A Palmer

    Brookhaven National Laboratory