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arXiv · 2205.09792

Persistent photogenerated state attained by femtosecond laser irradiation of thin $T_d$-MoTe$_2$

Meixin Cheng·Shazhou Zhong·Nicolás Rivas·Tina Dekker·Ariel Alcides Petruk·Patrick Gicala·Kostyantyn Pichugin·Fangchu Chen·Xuan Luo·Yuping Sun·Adam W. Tsen·Germán Sciaini
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Abstract

Laser excitation has emerged as a means to expose hidden states of matter and promote phase transitions on demand. Such laser induced transformations are often rendered possible owing to the delivery of spatially and/or temporally manipulated light, carrying energy quanta well above the thermal background. Here, we report time-resolved broadband femtosecond (fs) transient absorption measurements on thin flakes of Weyl semimetal candidate $T_d$-MoTe$_2$ subjected to various levels and schemes of fs-photoexcitation. Our results reveal that impulsive fs-laser irradiation alters the interlayer behavior of the low temperature $T_d$ phase as evidenced by the persistent disappearance of its characteristic coherent $^1$A$_1$ $=$ 13 cm$^{-1}$ shear phonon mode. We found that this structural transformation withstands thermal annealing up to 500 K, although it can be reverted to the 1$T$\' phase by fs-laser treatment at room temperature. Our work opens the door to reversible optical control of topological properties.

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Meixin Cheng, Shazhou Zhong, Nicolás Rivas, Tina Dekker, Ariel Alcides Petruk, Patrick Gicala, Kostyantyn Pichugin, Fangchu Chen, Xuan Luo, Yuping Sun, Adam W. Tsen, Germán Sciaini. 2022-05-14. Persistent photogenerated state attained by femtosecond laser irradiation of thin $T_d$-MoTe$_2$. https://arxiv.org/abs/2205.09792

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