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报告题目：Ultrafast order parameter dynamics in density waves systems

报告人：Prof. Dr. Jure Demsar, Institute of Physics, Johannes Gutenberg-University Mainz, Germany

报告时间：2022年03月01日（周二）下午16:00

报告地点：线上

报告摘要：

Intertwined order parameters are ubiquituos to advanced quantum solids, with the interplay between the different degrees of freedom (charge, spin, lattice) being responsible for their functional properties. Real-time femtosecond techniques^1-5 offer means to investigate the coupling strengths between the different degrees of freedoms as well as their manipulation,^5-8 that may lead to light-induced metastable states.^5-9 Charge density wave (CDW) systems present a prototype system with a coupled electronic and lattice orders, and have been extensively studied by different ultrafast spectroscopic methods.^1-6 Here, I will first focus on the order parameter dynamics in a prototype quasi one-dimensional Peierls CDW system K_0.3MoO₃, and address recent studies of an unconventional CDW order in BaNi₂As₂.¹⁰

[1] H. Schäfer, et al., Phys. Rev. Lett. 105, 066402 (2010).

[2] M. Eichberger, et al., Nature 468, 799 (2010).

[3] F. Schmitt, et al., Science 321, 1649 (2008).

[4] T. Rohwer, et al., Nature 471, 490 (2011).

[5] T. Huber, et al., Phys. Rev. Lett. 113, 026401 (2014).

[6] L. Stojchevska, et al., Science 344, 177 (2014).

[7] K. W. Kim, et al., Nature Materials 11, 497 (2012).

[8] M. Mitrano, et al., Nature 530, 461 (2016).

[9] F. Pressacco, et al., Nature Communications 12, 5088 (2021).

[10] A.R. Pokharel, et al., arxiv:2102.09926

报告人简介：

Dr. Jure Demsar is a Professor of experimental solid state physics at the Johannes Gutenberg-University Mainz. His group focuses on real-time spectroscopy and manipulation of symmetry-broken ground states, using lab-based time-resolved techniques like broad-band optical spectroscopy, electron diffraction and THz spectroscopy, and is involved in experiments at large-scale facilities using intense narrow band THz excitation, time-resolved photoelectron spectroscopy, and X-ray diffraction. The group focuses on nonequilibrium phenomena in superconductors, interplay of superconductivity with competing orders, dynamics and photoinduced phase transitions in density wave systems, correlations in heavy-electron systems, optical manipulation of antiferromagnets, and has been heavily involved implementing new data-acquisition and analysis approaches in time-resolved momentum microscopy.