2025/07/10 by Ono, Atsushi
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Optics (physics.optics) #Strongly Correlated Electrons (cond-mat.str-el)
paper · doi:10.48550/arxiv.2507.07680
We revisit the relationship between electric polarization modulation ΔP in ferroelectrics induced by a low-frequency pulsed electric field and the corresponding second harmonic intensity modulation ΔISH. Using nonlinear response theory, we derive their time-domain expressions linear in the pulse amplitude, revealing that not only the electric field but also its time derivative contributes to ΔISH. Furthermore, even when the time-derivative component is negligible, ΔISH can be in antiphase with the pulsed field and thus with ΔP. These theoretical predictions are further supported by real-time simulations of a model for electronic ferroelectrics. Our results demonstrate that the commonly assumed relation ΔP ∝ ΔISH can break down under certain conditions, reflecting the complex-valued and frequency-dependent nature of nonlinear dynamical susceptibilities.