Simultaneous Observation of Carrier-Specific Redistribution and Coherent Lattice Dynamics in 2H-MoTe2 with Femtosecond Core-Level Spectroscopy. uri icon

abstract

  • 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.

published proceedings

  • ACS Nano

altmetric score

  • 0.25

author list (cited authors)

  • Attar, A. R., Chang, H., Britz, A., Zhang, X., Lin, M., Krishnamoorthy, A., ... Leone, S. R.

citation count

  • 36

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

publication date

  • January 2020