Abstract

Advancements in laser technology have unlocked the potential to observe the real-time dynamics of nuclei on the femtosecond scale. Strontium titanate (SrTiO3) presents a unique case as a quantum paraelectric material characterized by its near-ferroelectric transition at low temperatures, which is inhibited by quantum nuclear fluctuations. I will present the first atomistic and ab initio simulation of the time-resolved quantum nuclear dynamics of SrTiO3 under pulsed THz radiation. Our novel approach [1] accurately replicates the spectral features identified in time-resolved X-ray signals (like energy upconversion [2]) without any fitted parameter but also reveals the complex energy redistribution processes among all modes following phonon-phonon scattering. We also show how it is possible to stabilize a dynamical ferroelectric phase [3,4] thanks to the transient strain induced by the nonlinear dynamics of nuclei. We demonstrate how first principles simulation can aid the design of nonequilibrium nuclear motion to stabilize hidden phases of matter.

[1] L Monacelli and F Mauri, Phys. Rev. B 103 , 104305 (2021) [2] M Kozina et al, Nat Phys, 15, 387 (2019) [3] T F Nova et al, Science, 364, 1075 (2019) [4] X Li et al, Science, 364, 1079 (2019)