研究課題
We have carried out Time-resolved hard X-ray photoelectron spectroscopy (trHAXPES) using microfocused X-ray free-electron laser (XFEL, hn =8 keV) pulses as a probe and infrared laser pulses (hn = 1:55 eV) as a pump to determine space-charge effects and separate out intrinsic charge-carrier recombination dynamics in La:SrTiO3. We have used a combination of experiments and numerical N-body simulations for developing a simple approach to characterize and decrease XFEL-induced vacuum space-charge effects, which otherwise pose a serious limitation to spectroscopy experiments. We then show that, using an analytical mean-field model, vacuum space-charge effects can be compensated by pump laser-induced photoholes at high excitation densities. This provides us a method to separate vacuum space-charge effects from the intrinsic charge-carrier recombination dynamics in the time domain. We then obtain pump laser induced charge carrier dynamics form the Ti 1s peak width and peak energy shift as function of time delay between the pump and the probe using trHAXPES. Our trHAXPES results thus open a route to studies of intrinsic charge-carrier dynamics on picosecond time scales with lateral spatial resolution on the micrometer scale.
すべて 2016
すべて 雑誌論文 (2件) (うち国際共著 1件、 査読あり 2件、 オープンアクセス 1件、 謝辞記載あり 1件) 図書 (1件)
Journal of Japanese Society for Synchrotron Radiation Research
巻: 29 ページ: 14 to 22
Scientific Reports
巻: 6 ページ: 35087-1 to 10
doi:10.1038/srep35087 (2016)
