Special Quantum Matter Seminar

Ultrafast photoexcitation and propagation of coherent magnons

Changmin Lee, Professor, Hanyang University (Korea),

Wavepackets of magnetization in magnetically ordered materials have emerged as a potential means to shuttle quantum information over large distances. In this talk, I will discuss how ultrafast laser pulses can generate coherent spin wavepackets in magnetically ordered systems and follow their subsequent motion. In particular, the time-resolved optical measurements of wavepacket propagation in the Kagome ferromagnet Fe3Sn2 demonstrate that the spin information arrives at times significantly less than . The arrival of magnetization at a remote location occurs in a time far shorter than expected from the spin wave velocity. We show that this "precursor" originates from the long-range magnetic dipole interaction [1]. Related effects may have far-reaching consequences toward realizing long-range transport of spin information [2].

References

[1] C. Lee, Y. Sun, L. Ye, S. Rathi, K. Wang, Y.-M. Lu, J. Moore, J. G. Checkelsky, and J. Orenstein, Spin wavepackets in the Kagome ferromagnet Fe3Sn2: propagation and precursors, Proc. Natl. Sci. Acad. 120, e2220589120 (2023).

[2] Y. Sun, F. Meng, C. Lee, J. Orenstein, et al., Universal spin wavepacket transport in van der Waals antiferromagnets. arXiv:2309.03278, Nature Physics, in press (2024).

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For more information, please contact Bonnie Leung by email at [email protected].