Aaron Lindenberg, an assistant professor at SLAC and Stanford, will deliver this week’s Photon Science Seminar, “Ultrafast Atomic-scale Processes in Nanoscale Materials,” at 3 p.m. Wednesday, May 7, in Building 901′s Redtail Hawk Room.
Lindenberg, who is associated with the Stanford PULSE Institute and Stanford Institute for Materials and Energy Sciences, will describe experiments carried out at SLAC’s Linac Coherent Light Source (LCLS) X-ray laser and Stanford Synchrotron Radiation Lightsource (SSRL) that probed the first steps associated with nanoscale transormations at the atomic length scale and femtosecond and picosecond timescales.
One of the studies, conducted at LCLS, focused on the mechanistic transformation pathways underlying shock-induced and light-induced phase transitions in cadmium selenide and cadmium sulfide nanocrystals. These measurements, Lindenberg will explain, demonstrated the first experimental evidence of a theoretically predicted but not previously observed intermediate/transition state. They also showed how X-rays enable tomographic visualization of nanoscale shape-change dynamics and large-amplitude reversible strains occurring within semiconductor nanowires on femtosecond timescales.
Lindenberg will also describe a study at SSRL that focused on single-cycle terahertz-induced structural responses in nanoscale ferroelectric thin films, including barium titanate and bismuth ferrite, using applied light fields as a means of all-optically biasing these materials on sub-picosecond timescales, coupled with both X-ray scattering and nonlinear optical probes. The measurements from this experiment revealed large-amplitude electric-field-induced polarization dynamics, changes in the unit cell structure, and strains.