Laser-Induced Transient Magnons in Sr₃Ir₂O₇ Throughout the Brillouin Zone

Although ultrafast manipulation of magnetism holds great promise for new physical phenomena and applications, targeting specific states is held back by our limited understanding of how magnetic correlations evolve on ultrafast timescales. Using ultrafast resonant inelastic x-ray scattering [1-3] we demonstrate that femtosecond laser pulses can excite transient magnons at large wavevectors in the gapped antiferromagnet Sr₃Ir₂O₇, and that they persist for several picoseconds which is opposite to what is observed in the nearly gapless magnet Sr₂IrO₄ [1]. Our work suggests that materials with isotropic magnetic interactions are preferred to achieve rapid manipulation of magnetism.

[1] M. P. M. Dean,et al., Nature Materials 15, 601 (2016).
[2] M. Mitrano.et al., Science Advances 5, eaax3346 (2019).
[3] S. Parchenko, et al., Phys. Rev. Research 2, 023110 (2020)