Revealing excitonic processes and chemical bonding in MoS2 by x-ray spectroscopy

Article

关键词: TRANSITION-METAL DICHALCOGENIDES;    ELECTRONIC-STRUCTURE;    ABSORPTION-SPECTROSCOPY;    AUGER;    THRESHOLD;    EDGE;    MOLYBDENUM;    STATES;    PHOTOLUMINESCENCE;    SPECTRA;   

DOI  :  10.1103/PhysRevB.98.115149

来源: SCIE

【 摘 要 】

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 two-dimensional transition-metal dichalcogenide MoS2, we demonstrate that these effects have significant manifestations at the S K 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 postcollision interaction effect. Our interpretation is supported by comparison of both the photoemission valence-band spectrum and the S K-edge x-ray-absorption spectrum with electronic structure calculations and an ab initio solution of the Bethe-Salpeter equation that accurately accounts for the electron-core-hole interaction.

【 授权许可】

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