Ultrafast polarization switching of (BaSr)TiO₃ thin film by a single-period terahertz pulse in a vicinity of phase transition

Abstract

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

“…This is quite expected, since there is a component in the polarization that coincides with the direction of the terahertz field (in the film plane). On the other hand, three types of domains oriented at 120 degrees relative to each other can reduce the signal [ 51 ]. However, when considering terahertz excitation, we take into account the crystallography of the unit cell.…”

Ferroelectric Polarization Reversal vs Pump Spot Shape

“…However, special attention should be paid to the size effects in these samples and their influence on the crystal structure [46,47]. I note that a 𝜋/2 polarization rotation induced by a strong single-cycle terahertz pulse in some domains of a multidomain ferroelectric thin film of (Ba 0.8 Sr 0.2 )TiO 3 , where the depolarized field should be reduced due to the natural shape of the domains, was claimed recently in [15][16][17].…”

“…At the same time, the situation in ferroelectrics turned out to be more complicated [10]. The original proposal to switch the polarization by resonant excitation of the ferroelectric mode [11][12][13] has not yet been fully realized experimentally [14][15][16][17]. It was also shown that optical pumping with excitation of the electronic subsystem [18][19][20][21] leads only to a temporary decrease in polarization [22][23][24][25].…”