Attosecond Time-Domain Measurement of Core-Level-Exciton Decay in Magnesium Oxide

Authors

Romain Géneaux, University of California, Berkeley
Christopher J. Kaplan, University of California, Berkeley
Lun Yue, Louisiana State University
Andrew D. Ross, University of California, Berkeley
Jens E. Bækhøj, Louisiana State University
Peter M. Kraus, University of California, Berkeley
Hung Tzu Chang, University of California, Berkeley
Alexander Guggenmos, University of California, Berkeley
Mi Ying Huang, University of California, Berkeley
Michael Zürch, University of California, Berkeley
Kenneth J. Schafer, Louisiana State University
Daniel M. Neumark, University of California, Berkeley
Mette B. Gaarde, Louisiana State University
Stephen R. Leone, University of California, Berkeley

Document Type

Article

Publication Date

5-22-2020

Abstract

Excitation of ionic solids with extreme ultraviolet pulses creates localized core-level excitons, which in some cases couple strongly to the lattice. Here, core-level-exciton states of magnesium oxide are studied in the time domain at the Mg L2,3 edge with attosecond transient reflectivity spectroscopy. Attosecond pulses trigger the excitation of these short-lived quasiparticles, whose decay is perturbed by time-delayed near-infrared pulses. Combined with a few-state theoretical model, this reveals that the infrared pulse shifts the energy of bright (dipole-allowed) core-level-exciton states as well as induces features arising from dark core-level excitons. We report coherence lifetimes for the two lowest core-level excitons of 2.3±0.2 and 1.6±0.5 fs and show that these are primarily a consequence of strong exciton-phonon coupling, disclosing the drastic influence of structural effects in this ultrafast relaxation process.

Publication Source (Journal or Book title)

Physical Review Letters

Recommended Citation

Géneaux, R., Kaplan, C., Yue, L., Ross, A., Bækhøj, J., Kraus, P., Chang, H., Guggenmos, A., Huang, M., Zürch, M., Schafer, K., Neumark, D., Gaarde, M., & Leone, S. (2020). Attosecond Time-Domain Measurement of Core-Level-Exciton Decay in Magnesium Oxide. Physical Review Letters, 124 (20) https://doi.org/10.1103/PhysRevLett.124.207401