Modeling of ultrafast polarization switching in PbTiO3

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

“…No permanent switching was observed after the end of the pulses. A possible reason has been suggested in [ 18 ]. It is stated that a single-pulse excitation of a sufficient intensity will always lead to sample depolarization due to the chaotic dynamics of a system of coupled harmonic oscillators with a symmetric potential well.…”

“…At present, there are some theoretical [ 14 , 15 , 16 , 17 , 18 ] and experimental works that show the possibility of influencing the ferroelectric order parameter with optical [ 19 , 20 , 21 ] or THz pulses. The THz-induced change in polarization can be directly measured as a dynamical polar ion displacement with time-resolved X-ray diffraction [ 22 ].…”

“…Several theoretical works [ 18 , 30 ] predicted a higher impact on polarization with the direct excitation of higher-frequency modes (IR or Raman) rather than the low-frequency soft mode; the process is followed by the excitation of the soft mode due to the phonon–phonon interaction. The experiment was realized in LiNbO 3 [ 30 ] with the resonant excitation of the Q IR mode with the frequency of 19 THz, which led to polarization modulation detected by the SHG technique.…”

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

“…Such a model could provide optimal pulse parameters and answer a series of questions, such as which normal mode should receive energy injection; whether energy should be injected directly into the mode that leads to switching or another strongly coupled mode; whether it is beneficial to use a series of pulses; which pulse polarization is optimal for switching; whether pulse shape affects switching; and which ferroelectric material is best suited for ultrafast switching of electric polarization, among others. In this research, we improved and tested a theoretical model for ultrafast polarization switching, which has previously been proposed in various studies. ,− To calculate material constants of ferroelectrics as oxides and chalcogenides, first-principles methods like density functional theory (DFT) are often utilized . These methods are effective in determining the structure of stable polarized states, energy barriers, ions’ effective charges, polarization values, and the phonon spectrum. ,− Moreover, it is important to highlight that DFT calculations’ results are highly dependent on the chosen exchange–correlation functional .…”

“…In this research, we improved and tested a theoretical model for ultrafast polarization switching, which has previously been proposed in various studies. 4 , 11 − 13 To calculate material constants of ferroelectrics as oxides and chalcogenides, first-principles methods like density functional theory (DFT) are often utilized. 14 These methods are effective in determining the structure of stable polarized states, energy barriers, ions’ effective charges, polarization values, and the phonon spectrum.…”