Light-Induced Subpicosecond Lattice Symmetry Switch in MoTe2

• Published in: Physical review. X Vol. 9; no. 2
• Main Authors: Zhang, M Y, Wang, Z X, Li, Y N, Shi, L Y, D. Wu, Lin, T, Zhang, S J, Liu, Y Q, Liu, Q M, Wang, J, Dong, T, Wang, N L
• Format: Journal Article
• Language: English
• Published: College Park American Physical Society 22.05.2019
• Subjects: Conduction bands; Electronic properties; Excitation; Femtosecond pulses; Infrared lasers; Lasers; Metalloids; Optical control; Optical properties; Oscillation modes; Phase transitions; Phases; Second harmonic generation; Topology; Transition metals
• ISSN: 2160-3308
• DOI: 10.1103/PhysRevX.9.021036

The recent development of ultrashort laser pulses allows for optical control of structural and electronic properties of complex quantum materials. The layered transition-metal dichalcogenideMoTe2, which can crystallize into several different structures with distinct topological and electronic properties, provides possibilities to control or switch between different phases. In this study, we report a photoinduced subpicosecond structural transition between the type-II Weyl semimetal phase and normal-semimetal phase in bulk crystallineMoTe2by using ultrafast pump-probe and time-resolved second-harmonic-generation spectroscopy. The phase transition is most clearly characterized by the dramatic change of the shear oscillation mode and the intensity loss of second-harmonic generation. This work opens up new possibilities for ultrafast manipulation of the topological properties of solids, enabling potentially practical applications for a topological switch device with ultrafast excitations.