engleski

Photoemission properties of organic chain compounds

In this work we extend our previous considerations of the spectral properties of quasi-one-dimensional bands using the $G_0W_0$ approximation with the three-dimensional long-range Coulomb electron-electron interaction for the calculation of the one-particle spectral function to TTF-TCNQ. Represented in the model with two one-dimensional electron bands per donor and acceptor chains this compound has a dispersive low energy collective mode due to the strong coupling between the plasmon and the dipolar mode, together with the mode at energies order of magnitude higher. Since the dispersion of the first mode spreads through the whole low-energy range from zero up to its longitudinal value, it is responsible for the absence of the low-energy quasi-particle and the appearance of broad dispersion at these energies, while the wide structure at higher energies is due to the dispersion of the second mode. Obtained spectral properties are in qualitative agreement with the ARPES data for TTF-TCNQ.

G_0W_0 approximation; Collective mode; Spectral function

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