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Electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ

M. Sing·U. Schwingenschlögl·R. Claessen·P. Blaha·J. M. P. Carmelo·L. M. Martelo·P. D. Sacramento·M. Dressel·C. S. Jacobsen
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Abstract

We study the electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ by means of density-functional band theory, Hubbard model calculations, and angle-resolved photoelectron spectroscopy (ARPES). The experimental spectra reveal significant quantitative and qualitative discrepancies to band theory. We demonstrate that the dispersive behavior as well as the temperature-dependence of the spectra can be consistently explained by the finite-energy physics of the one-dimensional Hubbard model at metallic doping. The model description can even be made quantitative, if one accounts for an enhanced hopping integral at the surface, most likely caused by a relaxation of the topmost molecular layer. Within this interpretation the ARPES data provide spectroscopic evidence for the existence of spin-charge separation on an energy scale of the conduction band width. The failure of the one-dimensional Hubbard model for the {\it low-energy} spectral behavior is attributed to interchain coupling and the additional effect of electron-phonon interaction.

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M. Sing, U. Schwingenschlögl, R. Claessen, P. Blaha, J. M. P. Carmelo, L. M. Martelo, P. D. Sacramento, M. Dressel, C. S. Jacobsen. 2003-04-11. Electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ. https://doi.org/10.1103/physrevb.68.125111

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