Simultaneous Observation of Carrier-Specific Redistribution and Coherent Lattice Dynamics in 2H-MoTe2 with Femtosecond Core-Level Spectroscopy.
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We employ few-femtosecond extreme ultraviolet (XUV) transient absorption spectroscopy to reveal simultaneously the intra- and interband carrier relaxation and the light-induced structural dynamics in nanoscale thin films of layered 2H-MoTe2 semiconductor. By interrogating the valence electronic structure via localized Te 4d (39-46 eV) and Mo 4p (35-38 eV) core levels, the relaxation of the photoexcited hole distribution is directly observed in real time. We obtain hole thermalization and cooling times of 15 5 fs and 380 90 fs, respectively, and an electron-hole recombination time of 1.5 0.1 ps. Furthermore, excitations of coherent out-of-plane A1g (5.1 THz) and in-plane E1g (3.7 THz) lattice vibrations are visualized through oscillations in the XUV absorption spectra. By comparison to Bethe-Salpeter equation simulations, the spectral changes are mapped to real-space excited-state displacements of the lattice along the dominant A1g coordinate. By directly and simultaneously probing the excited carrier distribution dynamics and accompanying femtosecond lattice displacement in 2H-MoTe2 within a single experiment, our work provides a benchmark for understanding the interplay between electronic and structural dynamics in photoexcited nanomaterials.
author list (cited authors)
Attar, A. R., Chang, H., Britz, A., Zhang, X., Lin, M., Krishnamoorthy, A., ... Leone, S. R.
complete list of authors
Attar, Andrew R||Chang, Hung-Tzu||Britz, Alexander||Zhang, Xiang||Lin, Ming-Fu||Krishnamoorthy, Aravind||Linker, Thomas||Fritz, David||Neumark, Daniel M||Kalia, Rajiv K||Nakano, Aiichiro||Ajayan, Pulickel||Vashishta, Priya||Bergmann, Uwe||Leone, Stephen R