Ultrafast Dynamics of Electrons and Ions and Their Interplay an Complex Oxides
Abstract: The quest for new states of matter in the time domain and the need for ultrafast control of material properties have been fueled by recent advances in large-scale ultrafast X-ray facilities. These new experimental capabilities enable direct probing of structural dynamics with unprecedented spatial and temporal resolution, shedding light on fundamental dynamical processes in materials.
Combining ultrafast X-ray and optical probes, I will show how the electronic and structural dynamics intertwine in complex oxides and how these transient properties can be controlled on ultrafast time scales. In the first example, optical and terahertz excitation offer new pathways for controlling ferroelectric phases, including inducing large strain, creating new three-dimensional ferroelectric structures, and driving intrinsic modes of ferroelectric vortices. In the second example, an unconventional slowing down of charge ordering was observed in iron-based perovskites. Density function theory calculation shows that this nonthermal slowing down of electronic recovery can be traced to the magnetic interaction of the system. Looking into the future, recent progress in developing multimodal, multiscale X-ray imaging platform will be discussed to go beyond ensemble average for studying localized dynamics.