Intrinsic 1$${T}^{{\prime} }$$ phase induced in atomically thin 2H-MoTe2 by a single terahertz pulse
Jiaojian Shi, Ya‐Qing Bie, Alfred Zong, Shiang Fang, Wei Chen, Jinchi Han, Zhaolong Cao, Yong Zhang, Takashi Taniguchi, Kenji Watanabe, Xuewen Fu, Vladimir Bulović, Efthimios Kaxiras, Edoardo Baldini, Pablo Jarillo‐Herrero, Keith A. Nelson
Abstract
Abstract The polymorphic transition from 2 H to 1 $${T}^{{\prime} }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow> <mml:mi>T</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>′</mml:mo> </mml:mrow> </mml:msup> </mml:math> -MoTe 2 , 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 $${T}^{{\prime} }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow> <mml:mi>T</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>′</mml:mo> </mml:mrow> </mml:msup> </mml:math> 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 $${T}^{{\prime} }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow> <mml:mi>T</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>′</mml:mo> </mml:mrow> </mml:msup> </mml:math> lattice after irradiating a mono- or few-layer 2 H -MoTe 2 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 2 H -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 2 but also highlight the unique capability of strong-field terahertz pulses in manipulating quantum materials.