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Bibliographic Details
Main Authors: Cheng, Bing, Kramer, Patrick L., Trigo, Mariano, Liu, Mengkun, Uher, Ctirad, Reis, David A., Shen, Zhi-Xun, Sobota, Jonathan A., Hoffmann, Matthias. C.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2408.05770
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Table of Contents:
  • Driving coherent lattice motion with THz pulses has emerged as a novel pathway for achieving dynamic stabilization of exotic phases that are inaccessible in equilibrium quantum materials. In this work, we present a previously unexplored mechanism for THz excitation of Raman-active phonons. We show that intense THz pulses centered at 1 THz can excite the Raman-active $A_{1g}$ phonon mode at 2.9 THz in a bismuth film. We rule out the possibilities of the phonon being excited through conventional anharmonic coupling to other modes or via a THz sum frequency process. Instead, we demonstrate that the THz-driven tunnel ionization provides a plausible means of creating a displacive driving force to initiate the phonon oscillations. Our work highlights a new mechanism for exciting coherent phonons, offering potential for dynamic control over the electronic and structural properties of semimetals and narrow-band semiconductors on ultrafast timescales.