| Direct Structural Characterization of Photo-induced Coherent Phonon Oscillations in BaFe2As2 | |
| Abstract ID | 113 |
| Presenter | Simon Gerber |
| Presentation Type | Poster |
| Full Author List | W.-S. Lee, Y. Zhang, M. Yi, P.S. Kirchmann, R.G. Moore, D. Zhu, G.L. Dakowski, O. Krupin, M. Chollet, J.J. Turner, J.-S. Lee, A. Mehta, H.-H. Kuo, I.R. Fisher, K.W. Kim, M. Wolf, Y.-D. Chuang, Z. Hussain, C.-C. Kao, T.P. Devereaux, and Z.-X. Shen |
| Affiliations |
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory |
| Category | |
| Abstract |
Insight into the relationship between the intertwined lattice, spin and orbital degrees of freedom is vital for the understanding of high-temperature superconductivity in iron-based materials. We address this question via ultrafast x-ray scattering to measure the time-evolution of a lattice Bragg peak in photo-excited BaFe2As2. Upon excitation with a femtosecond optical laser pulse, we observe an ultrafast increase and oscillation of the Bragg peak intensity with a frequency that is consistent with the coherent excitation of an A1g phonon mode. This mode modulates the Fe-As-Fe bond angle, which is crucial for determining the underlying electronic structure and also correlated with the superconducting transition temperature. We estimate the variation of the bond angle in this photo-induced coherent state by modeling the diffracted intensity of the Bragg peak in the presence of the A1g phonon mode. Our observations provide a direct view on the dynamics of the lattice degree of freedom that cannot be obtained by other means. |
| Footnotes |
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| Funding Acknowledgement | |