Snapshots of a light-induced metastable hidden phase driven by the collapse of charge order

• Published in: Science advances Vol. 8; no. 29; p. eabp9076
• Main Authors: Gao, Frank Y., Zhang, Zhuquan, Sun, Zhiyuan, Ye, Linda, Cheng, Yu-Hsiang, Liu, Zi-Jie, Checkelsky, Joseph G., Baldini, Edoardo, Nelson, Keith A.
• Format: Journal Article
• Language: English
• Published: United States AAAS 22.07.2022; American Association for the Advancement of Science
• Subjects: Condensed Matter Physics; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Materials Science; Physical and Materials Sciences; SciAdv r-articles
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.abp9076

Nonequilibrium hidden states provide a unique window into thermally inaccessible regimes of strong coupling between microscopic degrees of freedom in quantum materials. Understanding the origin of these states allows the exploration of far-from-equilibrium thermodynamics and the development of optoelectronic devices with on-demand photoresponses. However, mapping the ultrafast formation of a long-lived hidden phase remains a longstanding challenge since the initial state is not recovered rapidly. Here, using state-of-the-art single-shot spectroscopy techniques, we present a direct ultrafast visualization of the photoinduced phase transition to both transient and long-lived hidden states in an electronic crystal, 1 T -TaS 2 , and demonstrate a commonality in their microscopic pathways, driven by the collapse of charge order. We present a theory of fluctuation-dominated process that helps explain the nature of the metastable state. Our results shed light on the origin of this elusive state and pave the way for the discovery of other exotic phases of matter. A suite of advanced single-shot spectroscopies is used to track the ultrafast formation of a metastable hidden phase.