麻省理工学院

腾讯视频会议号：835 398 184，密码：231226

报告人简介

Dr. Honglie Ning is a condensed matter experimentalist focused on investigating the emergent phenomena in light-driven quantum materials employing a suite of time-resolved techniques, including optical spectroscopy and polarimetry spanning from terahertz to visible light range, electron and X-ray scattering, and angle-resolved photoemission spectroscopy. Currently Dr. Ning is a postdoctoral researcher in the Department of Physics at Massachusetts Institute of Technology. Prior to his current position, he earned the Ph.D. degree from the Department of Physics at California Institute of Technology in 2022, and obtained his B.S. degree in physics with Honors from Peking University in 2016.

报告摘要

Ultrafast laser excitation provides diverse pathways to transiently modulate order parameters, enabling nonthermal control of quantum phases that are inaccessible in equilibrium. Leveraging probes directly coupled to the order parameters, a plethora of dipolar-ordered phases has been experimentally manipulated on the ultrafast timescale. However, states exhibiting more exotic dipolar and higher multipolar orders remain elusive owing to the challenge of both directly manipulating and detecting them with light. In this talk, I will present an ultrafast protocol to address these issues by exploiting the intricate interaction between the electronic orders and coherent phonon excitations. In the first example, I will show evidence of excitonic order reversal in Ta2NiSe5 based on the anomalous behavior of its coupled phonons. In the second part, I will show that the dynamical transition to a hidden spin-orbit entangled quadrupolar ordered state in Ca2RuO4 is manifested through anomalies in the temperature, pump excitation fluence, and probe photon energy dependence of the strongly coupled phonon. Our methodology can be generally applied across strongly correlated materials to identify and manipulate exotic order parameters that typically elude conventional probes, with potential application to high-speed electronics beyond conventional spin- and charge-dipolar ordered materials.

邀请人：廉    超 副研究员

联系人：万    源 研究员

              汪非凡 副研究员
              田春璐  cltian@iphy.ac.cn

主办方：中国科学院物理研究所、松山湖材料实验室