Quenched lattice fluctuations in optically driven SrTiO3.
Nature materials 23:3 (2024) 363-368
Abstract:
Crystal lattice fluctuations, which are known to influence phase transitions of quantum materials in equilibrium, are also expected to determine the dynamics of light-induced phase changes. However, they have only rarely been explored in these dynamical settings. Here we study the time evolution of lattice fluctuations in the quantum paraelectric SrTiO3, in which mid-infrared drives have been shown to induce a metastable ferroelectric state. Crucial in these physics is the competition between polar instabilities and antiferrodistortive rotations, which in equilibrium frustrate the formation of long-range ferroelectricity. We make use of high-intensity mid-infrared optical pulses to resonantly drive the Ti-O-stretching mode at 17 THz, and we measure the resulting change in lattice fluctuations using time-resolved X-ray diffuse scattering at a free-electron laser. After a prompt increase, we observe a long-lived quench in R-point antiferrodistortive lattice fluctuations. Their enhancement and reduction are theoretically explained by considering the fourth-order nonlinear phononic interactions to the driven optical phonon and third-order coupling to lattice strain, respectively. These observations provide a number of testable hypotheses for the physics of light-induced ferroelectricity.Optically induced umklapp shift currents in striped cuprates
Physical Review B American Physical Society (APS) 109:4 (2024) 045150
Resonant enhancement of photo-induced superconductivity in K3C60
Nature Physics Springer Nature 19:12 (2023) 1821-1826
Theory for anomalous terahertz emission in striped cuprate superconductors
Physical Review B American Physical Society (APS) 108:18 (2023) l180508
Superconducting nonlinear transport in optically driven high-temperature K3C60.
Nature communications 14:1 (2023) 7233