Department of Materials, ETH Zürich
Ordering in solid-state materials determines their unique property and functionality. Ultrashort light pulses at visible, near infrared, and THz wavelength ranges offer the opportunity to probe and control the electronic, phononic, magnetic, and even time ordering in those materials. In this talk, I will first introduce the concept and verification of the ferroelectric polaron, a photo-carrier induced ordering, in dynamically disordered semiconductors [1,2]. Then I will switch to the probing of electronic and crystallographic ordering based on nonlinear optical processes, including two-dimensional optical Kerr effect  and second harmonic generation spectroscopy. Lastly, I will demonstrate some on-going projects and ideas on the light field driven ordering, e.g., dynamical multiferroic ordering and Floquet time ordering in quantum materials.
 Feifan Wang, Yongping Fu, Mark E. Ziffer, Yanan Dai, Sebastian F. Maehrlein, and X.-Y. Zhu. Solvated electrons in solids - Ferroelectric large polarons in lead halide perovskites. J. Am. Chem. Soc. 2021, 143, 5–16.
 Feifan Wang, Weibin Chu, Lucas Huber, Teng Tu, Yanan Dai, Jue Wang, Hailin Peng, Jin Zhao, and X.-Y. Zhu. Phonon signatures for polaron formation in an anharmonic semiconductor. Proc. Natl. Acad. Sci. U.S.A. 2022, accepted.
 Feifan Wang, Lucas Huber, Sebastian F. Maehrlein, and X.-Y. Zhu. Optical anisotropy and phase transitions in lead halide perovskites. J. Phys. Chem. Lett. 2021, 12, 5016–5022.
Dr. Wang received his BS from Shandong University in 2012. He did his Ph.D. study under the supervision of Prof. Dongsheng Xu in Peking University (2012-2017). Then he worked as a postdoctoral research scientist in the lab of Prof. Xiaoyang Zhu at Columbia University (2017-2021). From Sep. 2021 to now, he is appointed as a postdoctoral scientist in Prof. Manfred Fiebig’s group at ETH Zürich.
邀请人：孟 胜 研究员（9396）
联系人：张 萃 副研究员（8609）