Author:
Huang 黄 Chaozhi 超之,Xu 徐 Chengyang 骋洋,Zhu 朱 Fengfeng 锋锋,Duan 段 Shaofeng 绍峰,Liu 刘 Jianzhe 见喆,Gu 顾 Lingxiao 凌霄,Wang 王 Shichong 石崇,Liu 刘 Haoran 浩然,Qian 钱 Dong 冬,Luo 罗 Weidong 卫东,Zhang 张 Wentao 文涛
Abstract
High-resolution time- and angle-resolved photoemission measurements were conducted on the topological insulator ZrTe5. With strong femtosecond photoexcitation, a possible ultrafast phase transition from a weak to a strong topological insulating phase was experimentally realized by recovering the energy gap inversion in a time scale that was shorter than 0.15 ps. This photoinduced transient strong topological phase can last longer than 2 ps at the highest excitation fluence studied, and it cannot be attributed to the photoinduced heating of electrons or modification of the conduction band filling. Additionally, the measured unoccupied electronic states are consistent with the first-principles calculation based on experimental crystal lattice constants, which favor a strong topological insulating phase. These findings provide new insights into the longstanding controversy about the strong and weak topological properties in ZrTe5, and they suggest that many-body effects including electron–electron interactions must be taken into account to understand the equilibrium weak topological insulating phase in ZrTe5.
Subject
General Physics and Astronomy