高性能时间分辨角分辨光电子能谱在量子材料中的研究进展

High-performance time-and angle-resolved photoemission spectroscopy studies on quantum materials

通过飞秒激光激发固体材料,利用材料中不同自由度的响应时间尺度研究多体相互作用、追踪超快相变过程、实现光诱导新物态或隐藏态等,这是凝聚态物理研究的前沿和重要探索方向.时间分辨角分辨光电子能谱是近十多年发展起来的研究量子材料在飞秒激光激发后超快电子结构动力学的关键实验手段.本文回顾了基于非线性光学晶体和高阶倍频的时间分辨角分辨光电子能谱的基本原理和组成,以及利用其对量子材料的超快电子结构动力学进行的研究.主要包括四个方面的研究进展:(1)量子材料的非占据电子态探测;(2)光诱导的超快电子结构相变;(3)关联电子材料中电声相互作用强度确定;(4)光致新物态.最后,讨论了时间分辨角分辨光电子能谱未来可能的发展方向.

Exciting solid materials with femtosecond lasers enables the study of many-body interactions in quantum materials during non-equilibrium processes for the time scales of different degrees of freedom in materials may vary,and such nonthermal methods can lead to the realization of new or hidden states.As one of the frontier research areas in condensed matter physics,ultrafast electronic dynamics in quantum materials after photoexcitation can be studied using time-and angle-resolved photoemission spectroscopy as the key experimental tool.In this review,we focus on the use of nonlinear optical crystals and high-harmonic generation for time-and angle-resolved photoemission spectroscopy.We cover recent advances in the field,including(1)the probing of unoccupied electronic states in quantum materials,(2)the observation of light-induced ultrafast electronic phase transitions,(3)the measurement of microscopic electron-phonon coupling strength,and(4)the discovery of light-induced new states.