Shi Jiaojian, Bie Ya-Qing, Zong Alfred, Fang Shiang, Chen Wei, Han Jinchi, Cao Zhaolong, Zhang Yong, Taniguchi Takashi, Watanabe Kenji, Fu Xuewen, Bulović Vladimir, Kaxiras Efthimios, Baldini Edoardo, Jarillo-Herrero Pablo, Nelson Keith A
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
Nat Commun. 2023 Sep 22;14(1):5905. doi: 10.1038/s41467-023-41291-w.
The polymorphic transition from 2H to 1-MoTe, which was thought to be induced by high-energy photon irradiation among many other means, has been intensely studied for its technological relevance in nanoscale transistors due to the remarkable improvement in electrical performance. However, it remains controversial whether a crystalline 1 phase is produced because optical signatures of this putative transition are found to be associated with the formation of tellurium clusters instead. Here we demonstrate the creation of an intrinsic 1 lattice after irradiating a mono- or few-layer 2H-MoTe with a single field-enhanced terahertz pulse. Unlike optical pulses, the low terahertz photon energy limits possible structural damages. We further develop a single-shot terahertz-pump-second-harmonic-probe technique and reveal a transition out of the 2H-phase within 10 ns after photoexcitation. Our results not only provide important insights to resolve the long-standing debate over the light-induced polymorphic transition in MoTe but also highlight the unique capability of strong-field terahertz pulses in manipulating quantum materials.
从2H到1-MoTe₂的多晶型转变，在许多其他方式中，曾被认为是由高能光子辐照诱导的，由于其在纳米级晶体管中的技术相关性以及电性能的显著改善，已得到深入研究。然而，由于发现这种假定转变的光学特征与碲团簇的形成有关，所以晶体1相是否产生仍存在争议。在这里，我们展示了在用单个场增强太赫兹脉冲辐照单层或几层2H-MoTe₂后，形成了本征的1相晶格。与光脉冲不同，低太赫兹光子能量限制了可能的结构损伤。我们进一步开发了一种单脉冲太赫兹泵浦 - 二次谐波探测技术，并揭示了光激发后10纳秒内从2H相的转变。我们的结果不仅为解决关于MoTe₂中光致多晶型转变的长期争论提供了重要见解，还突出了强场太赫兹脉冲在操纵量子材料方面的独特能力。
