2025/10/01 by Sheikh Rubaiat Ul Haque, Haque, Sheikh Rubaiat Ul, Martin J. Cross +40
Engineering · Physics and Astronomy · #Acoustic Wave Resonator Technologies #FOS: Physical sciences #Mechanical and Optical Resonators #Strongly Correlated Electrons (cond-mat.str-el) #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.2510.00605
openalex publication_date 2025/10/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Strong-field terahertz (THz) excitations enable dynamic control over electronic, lattice and symmetry degrees of freedom in quantum materials. Here, we uncover pronounced terahertz-induced symmetry modulations and coherent phonon dynamics in the van der Waals antiferromagnet MnPS3, in which inversion symmetry is broken by its antiferromagnetic spin configuration. Time-resolved second harmonic generation measurements reveal long-lived giant oscillations in the antiferromagnetic phase, with amplitudes comparable to the equilibrium signal, driven by phonons involving percent-level atomic displacements relative to the equilibrium bond lengths. The temporal evolution of the rotational anisotropy patterns indicate a dynamic breaking of mirror symmetry, modulated by two vibrational modes at 1.7 THz and 4.5 THz, with the former corresponding to a hidden mode not observed in equilibrium spectroscopy. We show that these effects arise in part from a field-induced charge rearrangement mechanism that lowers the local crystal symmetry, and couples to the phonon modes. A long-lived field-driven response was uncovered with a complex THz polarization dependence which, in comparison to theory, indicates evidence for an antiferromagnetic-to-ferrimagnetic transition. Our results establish an effective field-tunable pathway for driving excitations otherwise weak in equilibrium, and for manipulating magnetism in low-dimensional materials via dynamical modulation of symmetry.