Betraying excitonic processes and chemical bonding in MoS2 by x-ray-absorption near-edge structure and resonant-Auger electron emission
Joseph Woicik, Nicholas F. Quackenbush, Conan Weiland, Eric L. Shirley, Abdul K. Rumaiz, Michael T. Brumbach, James M. Ablett
Electron core-hole processes at absorption edges sport several signatures, primarily in the form of bound states and/or excitonic enhancement. Through analysis of the resonant-Raman Auger effect for the 2-dimensional transition-metal dichalcogenide MoS2, we demonstrate that these effects can have significant manifestations at the S 1s x-ray edge. We characterize two asymmetric excitonically enhanced edges: one at the fundamental band edge and one several electron volts above it following a second band gap that lies entirely within the unoccupied states, with the latter revealing an anomalous post-collision interaction effect. Our interpretation is supported by comparison of the absorption spectra with electronic structure calculations obtained using an ab initio solution of the Bethe-Salpeter equation, which accurately accounts for the electron-core-hole interaction.
, Quackenbush, N.
, Weiland, C.
, , E.
, Rumaiz, A.
, Brumbach, M.
and Ablett, J.
Betraying excitonic processes and chemical bonding in MoS2 by x-ray-absorption near-edge structure and resonant-Auger electron emission, Physical Review B, [online], https://dx.doi.org/10.1103/PhysRevB.98.115149, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=926252
(Accessed September 20, 2021)