Transient Polarization Reversal using an Intense THz Pulse in Silicon‐Doped Lead Germanate

Abstract

The processes of dynamic polarization switching induced by the strong electric field of a nearly single‐cycle terahertz (THz) pulse are studied in a classical ferroelectric silicon‐doped lead germanate single crystal, Pb5(Ge0.74Si0.26)3O11, in THz pump–second‐harmonic‐generation (SHG) probe geometry depending on the pulse electric field strength (0.05–15.6 MV cm−1). Since the pump parameters correspond to the region of phonon excitations for a given material, THz‐induced polarization is explained by a dynamic change in the ferroelectric order parameter. Numerical solutions of the Landau–Khalatnikov equation using the thermodynamic potential constants for this material show that the effect of powerful THz pulses leads to polarization modulations and a strong nonlinear response, and is in good agreement with the experimental results. Oscillations of the nonlinear optical response after the end of the THz pulse are found, which can be associated with the excitation of the phonon mode in the crystal.

Ultrafast Polarization Switching in BaTiO3 Nanomaterials: Combined Density Functional Theory and Coupled Oscillator Study

“…The closest successful result to date, which involved reversible polarization change, was achieved by Mankowsky et al in their work on lithium niobate . Other studies − have also explored the selective excitation of lattice vibrations under ultrashort optical or THz pulses, which are essential for achieving practical polarization switching. The absence of a predictive model poses a significant obstacle to experimentally observing ultrafast switching of electric polarization.…”

Resonant Excitation of the Ferroelectric Soft Mode by a Narrow-Band THz Pulse

“…More often, the THz-induced change in polarization is probed optically, using second harmonic generation (SHG) or the optical Kerr effect. Using these effects, transient polarization switching or ultrafast polarization modulation was demonstrated in SrTiO 3 [25], an organic molecular dielectric [26], ferroelectric crystal BaTiO 3 [27], and PGO [28]. Recently, THz pulse excitation was shown to generate neuronic and synaptic behavior in relaxor ferroelectric Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) due to the activation of hidden phases [29], which can be considered as a type of ultrafast polarization switching in Nanomaterials 2023, 13,1961 2 of 10 this material.…”

Simulation of Ultrafast Polarization Switching in BaTiO₃

“…Although this possibility has garnered significant attention, it has not yet been observed experimentally.The closest successful result to date, which involved reversible polarization change, was achieved by Mankowsky et al in their work on lithium niobate [4]. Other studies [5][6][7][8][9][10] have also explored the selective excitation of lattice vibrations under ultra-short optical or THz pulses, which is essential for achieving practical polarization switching.…”