Light-induced charge density wave in LaTe3
Anshul Kogar, Alfred Zong, Pavel E. Dolgirev, Xiaozhe Shen, Joshua Straquadine, Ya‐Qing Bie, Xirui Wang, Timm Rohwer, I‐Cheng Tung, Yafang Yang, Renkai Li, Jie Yang, Stephen Weathersby, Suji Park, M. Kozina, Edbert J. Sie, Haidan Wen, Pablo Jarillo‐Herrero, I. R. Fisher, Xijie Wang, Nuh Gedik
Abstract
When electrons in a solid are excited with light, they can alter the free\nenergy landscape and access phases of matter that are beyond reach in thermal\nequilibrium. This accessibility becomes of vast importance in the presence of\nphase competition, when one state of matter is preferred over another by only a\nsmall energy scale that, in principle, is surmountable by light. Here, we study\na layered compound, LaTe$_3$, where a small in-plane (a-c plane) lattice\nanisotropy results in a unidirectional charge density wave (CDW) along the\nc-axis. Using ultrafast electron diffraction, we find that after\nphotoexcitation, the CDW along the c-axis is weakened and subsequently, a\ndifferent competing CDW along the a-axis emerges. The timescales characterizing\nthe relaxation of this new CDW and the reestablishment of the original CDW are\nnearly identical, which points towards a strong competition between the two\norders. The new density wave represents a transient non-equilibrium phase of\nmatter with no equilibrium counterpart, and this study thus provides a\nframework for unleashing similar states of matter that are "trapped" under\nequilibrium conditions.